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High HP engine mods? Lycoming thread.

Turbo69bird

Well Known Member
So what's available for engine mods. As a drag racer we know lots of stuff works to make big HP, cams, lifter, ported heads, turbos etc
What's available to us for our Experimental lycomings.

specific suppliers would be good to know also if it doesn't violate any VAF forum rules.

Anything you know of that will make more Hp for the experimental community is good to post.

I'm amazed that there's not more experimenting posted with experimentals in this area.
 
mods

I opted for cold air induction, 9:1, and dual EFII. It did 297 on the dyno.

Is it possible to get more HP, absolutely...but the cost is generally reliability.

If you really want more power, look to a turboprop...gobs of HP in a tiny little package...
 
I flew Steve Henry’s Highlander with a 300 HP Turbocharged Yamaha a month or so back....engine is about the same size as a Rotax (fits under the same cowl). Holy cow does it have power!! Have no idea how long it will last however..... ;)

Paul
 
Lyc Power

As a young guy, I built several 3SGTE (4-cyl turbo) cars as well as a mighty 2JZ Supra, eventually learned how to keep them together too! :p

However... none of those motors were built to deliver continuous max power like what's required in my airplane. Mostly because it was impossible to provide sufficient cooling at high boost settings. If you really want to know how to hot-rod an airplane engine, look to the sport class at Reno. Again, none of the really fast movers are likely to see any cross country or "general aviation" use, but turbo and supercharging are common. So are engine failures.

Bottom line - a plane isn't a car. The penalty for melting a piston, throwing a rod or breaking a half shaft is just money or maybe the distain of your competitors if you oil the track in the process. Not so in a plane.

That said, optimizing the (normally aspirated) performance of the 'ol Lyc is fair game, Barrett has it pretty much figured out with the 540's the Red Bull guys used.

I'll save my mod appetite for the new A90 I have on order. Got a JB4 and a Titan downpipe waiting for that sweet B58 bimmer motor just to get started :cool:
 
Let's talk turbos lycoming.

So I've built gas auto engines and turbo set ups.
I'm wondering why we don't see any turbo set ups on our experimental lycomings. Not turbo normalized but engines under boat for more Hp.

It's really not that hard to do but there are some hurdles to overcome.

Turbo needs to mount to a more robust, solid exhaust system not a slip fit, correct me if I'm wrong here but we use thick flanges and pipe for turbo set ups on cars
Turbo needs to be mounted high To drain oil back to engine or use a scavenge pump and tank set up.

Carb hats are pretty common and easily obtained. Carbs that are boost referenced are not available but there's always aftermarket Digital fuel injection like a fast xfi or other systems.

Waste gates can be used easy enough and plumbed back into exhaust system or parallel to it.
Blow off valve is a concern because it releases air/ fuel mixed would need to be vented to open air or blow back into intake steam somehow, (I've always just released to air.)
Cooling air (intercooler) is at a minimum which is just crazy since it's flowing all around you but it appears to be the case.
Location for air inlet, isn't as simple as on cars because of cooling air routing.

Anyone's thoughts on this are much appreciated.
 
It?s possible

My helicopter has a IO360 turboed up to 210 hp so it?s possible to turbo a lycoming. I thing the main problems would be fitting it in the cowl and getting rid of the heat. In the long run, I think it would only be beneficial for the planes that live at high altitudes. Ben
 
A very high percentage of the RV community can't cool stock power in a continuous long climb.
 
So I've built gas auto engines and turbo set ups.
I'm wondering why we don't see any turbo set ups on our experimental lycomings. Not turbo normalized but engines under boat for more Hp.

It's really not that hard to do but there are some hurdles to overcome.

Turbo needs to mount to a more robust, solid exhaust system not a slip fit, correct me if I'm wrong here but we use thick flanges and pipe for turbo set ups on cars
Turbo needs to be mounted high To drain oil back to engine or use a scavenge pump and tank set up.

Carb hats are pretty common and easily obtained. Carbs that are boost referenced are not available but there's always aftermarket Digital fuel injection like a fast xfi or other systems.

Waste gates can be used easy enough and plumbed back into exhaust system or parallel to it.
Blow off valve is a concern because it releases air/ fuel mixed would need to be vented to open air or blow back into intake steam somehow, (I've always just released to air.)
Cooling air (intercooler) is at a minimum which is just crazy since it's flowing all around you but it appears to be the case.
Location for air inlet, isn't as simple as on cars because of cooling air routing.

Anyone's thoughts on this are much appreciated.

There are a number of turboed Lycomings and Contis, mostly on Reno racers running crazy levels of boost.

Turbos can be rigidly mounted to the exhaust ports with very thick tubing but watch the thermal expansion at the junction of the pipes while handling the mechanical and vibrational loadings. Other method is to fix the turbo to the engine with a stout mount and use slip joints or bellows to handle the thermal expansion in the piping. This is lighter and more reliable in the long term.

You don't need a blow off valve on an airplane- or car for that matter. More weight and another thing to go wrong.

For RVs with their low Vne, boosted engines don't make a lot of sense for most cross country work at altitude and cooling in the climb on a hot day could be challenging.
 
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There are a number of turboed Lycomings and Contis, mostly on Reno racers running crazy levels of boost.

Turbos can be rigidly mounted to the exhaust ports with very thick tubing but watch the thermal expansion at the junction of the pipes while handling the mechanical and vibrational loadings. Other method is to fix the turbo to the engine with a stout mount and use slip joints or bellows to handle the thermal expansion in the piping. This is lighter and more reliable in the long term.

You don't need a blow off valve on an airplane- or car for that matter. More weight and another thing to go wrong.

For RVs with their low Vne, boosted engines don't make a lot of sense for most cross country work at altitude and cooling in the climb on a hot day could be challenging.


The blow off valve keeps the turbo from building pressure in the intake column and forcing the turbo to spin backwards without it when the throttle blades close it will spin backwards this is from 100,000 rpm and then people will say ?turbos aren't reliable I keep breaking mine.? lol. That?s why they came out with fat shaft turbos it was bandaid for people not running BOVs of course you shut the butterflies a lot less in an airplane than in a car. This is for blow through applications of course , draw through is what blew up so many performance boats in the 70s and gave turbos a really bad name.
 
My helicopter has a IO360 turboed up to 210 hp so it?s possible to turbo a lycoming. I thing the main problems would be fitting it in the cowl and getting rid of the heat. In the long run, I think it would only be beneficial for the planes that live at high altitudes. Ben

I have some good friends over by you w turbos cars you probably see them tearing up the streets in LI ones a 4cyl Pontiac making 800 hp half a Pontiac V8 in a GTO cool car. Out of the Shirley area. Another Th ET 455 v8 in port Jeff area.
 
The blow off valve keeps the turbo from building pressure in the intake column and forcing the turbo to spin backwards without it when the throttle blades close it will spin backwards this is from 100,000 rpm and then people will say “turbos aren't reliable I keep breaking mine.” lol. That’s why they came out with fat shaft turbos it was bandaid for people not running BOVs of course you shut the butterflies a lot less in an airplane than in a car. This is for blow through applications of course , draw through is what blew up so many performance boats in the 70s and gave turbos a really bad name.

I've built turbocharged road race, street and aircraft engines professionally for 40 years. Never used a blow off valve on one of them and never had a turbo failure on one of them either. None of the IMSA turbo engines from that great era used them to my knowledge...

I've assisted several Reno Sport Class winners running turbo engines- no BOVs there either, running over 90 inches.

You may notice in my signature that I've been flying a turbocharged RV for over 16 years- no blow off valve, original turbo.
 
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The saying goes..

More cylinders...

?There is no replacement for displacement.?

FWIW the 550-N series Continental (found in the Cirrus series) has at min 310HP at max 325 in the stock configuration . Also has 100 more lbs/ft of torque when compared with a stock 260HP 540. Torque is what makes your airplane go.

4 crank counterweights in the 550 leads to a very smooth ride too.

Installed weight is about 10lbs more than the Lyc. Fuel specifics are quite a bit better too.

Just sayin?...
 
What will you do with the power?

...Anything you know of that will make more Hp for the experimental community is good to post.

I'm amazed that there's not more experimenting posted with experimentals in this area.
Jeff, just curious, what will you do with that extra power in an RV? Is it for better climb? Flying much faster than VNE? Bragging rights? Racing? Towing a trailer? :D
 
?There is no replacement for displacement.?

FWIW the 550-N series Continental (found in the Cirrus series) has at min 310HP at max 325 in the stock configuration . Also has 100 more lbs/ft of torque when compared with a stock 260HP 540. Torque is what makes your airplane go.

4 crank counterweights in the 550 leads to a very smooth ride too.

Installed weight is about 10lbs more than the Lyc. Fuel specifics are quite a bit better too.

Just sayin?...

Hp is the determining factor in quantifying aircraft performance however. The extra 60 hp will be noticeable in climb performance mainly. Only worth a few percent in top speed.
 
Torque

“There is no replacement for displacement.”

Torque is what makes your airplane go.
Mark, Mark, Mark, ;)

Torque alone doesn't make anything go! Torque is a measurement of force only and is but one component required to motivate something. To actually move something, we need to do "work" which is defined as force x distance. And doing that "work" in a finite amount of time requires "power" which is amount of work performed in specific amount of time or work/time. For example, a car's brake can apply force or "torque" to the wheel(s) of a car parked on a hill to keep it from rolling, but it certainly can apply torque while rotating the wheel (work) and it definitely can't rotate the wheel very fast...

Let's try a little though experiment:

Imagine a person with a long torque wrench, say like this 3/4" drive 600 ft-lb model Torque Wrench

With this torque wrench, we can apply up to 600 ft-lbs of torque to something...maybe even a prop hub. How much torque did you say that IO-550-N makes at 2700 RPM and 310 HP?*

OK, so said person (or people) can use that wrench to apply torque to our airplane's prop hub, but to make the plane move we actually have to turn that prop, i.e. do work on it. Of course, even though our torque wrench person is capable of applying a lot of torque with that torque wrench, he's probably going to get tired after trying to turn our propeller more than a few revolutions (doing all that "work") but more importantly, he probably can't turn it very fast while applying all that torque, certainly not 2700 RPM. I.E. he can't make much power.

So you see, torque is not what makes airplanes go!

*So the IO-550-N making 310 hp at 2700 RPM is producing 603 ft-lbs of torque. How much power do we get with 603 ft-lbs of torque at only 2000 RPM? About 230. Is the plane going to go as fast with that same torque at 2000 RPM? Thus, as I said, it's actually power that makes our airplanes go fast.

Skylor

p.s. Horsepower = Torque*RPM/5252. Torque is our measurement of force, "revolution" is our measurement of distance (work) and "per minute" is our "over time". Power = work over time (work/time). The 5252 is simply a unit conversion factor of 550*60/Pi. Part of the reason that it's believed that "torque" is what makes things go is because aircraft engine output figures are very often compared at the same RPM (2700) and thus the torque values of engines of different power are directly comparable...but torque without a measurement of speed (RPM) does not tell us anything about the capability of an engine and how fast it can make an airplane go.
 
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$$$

Mark, Mark, Mark, ;)

Torque alone doesn't make anything go! Torque is a measurement of force only and is but one component required to motivate something. To actually move something, we need to do "work" which is defined as force x distance. And doing that "work" in a finite amount of time requires "power" which is amount of work performed in specific amount of time or work/time. For example, a car's brake can apply force or "torque" to the wheel(s) of a car parked on a hill to keep it from rolling, but it certainly can apply torque while rotating the wheel (work) and it definitely can't rotate the wheel very fast...

Let's try a little though experiment:

Imagine a person with a long torque wrench, say like this 3/4" drive 600 ft-lb model Torque Wrench

With this torque wrench, we can apply up to 600 ft-lbs of torque to something...maybe even a prop hub. How much torque did you say that IO-550-N makes at 2700 RPM and 310 HP?*

OK, so said person (or people) can use that wrench to apply torque to our airplane's prop hub, but to make the plane move we actually have to turn that prop, i.e. do work on it. Of course, even though our torque wrench person is capable of applying a lot of torque with that torque wrench, he's probably going to get tired after trying to turn our propeller more than a few revolutions (doing all that "work") but more importantly, he probably can't turn it very fast while applying all that torque, certainly not 2700 RPM. I.E. he can't make much power.

So you see, torque is not what makes airplanes go!

*So the IO-550-N making 310 hp at 2700 RPM is producing 603 ft-lbs of torque. How much power do we get with 603 ft-lbs of torque at only 2000 RPM? About 230. Is the plane going to go as fast with that same torque at 2000 RPM? Thus, as I said, it's actually power that makes our airplanes go fast.

Skylor

p.s. Horsepower = Torque*RPM/5252. Torque is our measurement of force, "revolution" is our measurement of distance (work) and "per minute" is our "over time". Power = work over time (work/time). The 5252 is simply a unit conversion factor of 550*60/Pi. Part of the reason that it's believed that "torque" is what makes things go is because aircraft engine output figures are very often compared at the same RPM (2700) and thus the torque values of engines of different power are directly comparable...but torque without a measurement of speed (RPM) does not tell us anything about the capability of an engine and how fast it can make an airplane go.

I?m sorry but I have to respectfully disagree with both of you, what makes airplanes go is money, lots of money. -Neil
 
I've built turbocharged road race, street and aircraft engines professionally for 40 years. Never used a blow off valve on one of them and never had a turbo failure on one of them either. None of the IMSA turbo engines from that great era used them to my knowledge...

I've assisted several Reno Sport Class winners running turbo engines- no BOVs there either, running over 90 inches.

You may notice in my signature that I've been flying a turbocharged RV for over 16 years-


So first off I?m happy to meet another turbo guy on here especially one flying a turbo RV. I would really like To see pictures of the set up and how you accomplished that.

I raced cars since 1987 been involved with drag racing, performance boats, atv racing and some Road racing mostly GT1.
Turbos are awesome and I?ve taught guys all over the world about them, My turbo set ups are in Australia, New Zealand uk, most everywhere.
I made my own headers in China for turbocharging Pontiacs so that guys could afford the systems here during a bleak economy. And helped size race turbos come up w cam grinds etc, for people since 2004. I think every car in should have turbo and a big one at that. Lol. I make 1000 hp on. A stock block , stock cast crank, iron heads.
and cruise at 17mpg with a 3.73 gear and the car stays cool as ice when out of boost. It far surpasses the naturally aspirated set ups I?ve run. I put 160 track passes a year on my engine for many years running 9 sec passes and drive it on the street and it?s got 9 years on it without even a spark plug change. So I lam
A big fan of turbos. And I appreciate everything you?ve done with turbos as well. Maybe I can learn something , I do still learn things every day about just about everything, that I?ve done for years. New ideas new ways and new products come up daily
And when you stop learning is when your in trouble . I never have a my way is the only way attitude towards anything

so I?ll ask you some questions.

Where does the fan blow the air when the butterflies close?

Does the turbo continue to spin freely without a blow off valve, and if so how?

Doesn?t that air it?s blowing continue to blow and build up and eventually spin the turbo backwards?

Not saying it can?t be done, but
Just because someone has done something it doesn?t make it the best way to do it.
Can you get away without it, possibly That?s a different question.

Lots of guys used draw through systems too but that?s what almost killed the turbo industry. Only the popularity of blow through turbos ion tractor trailers vs superchargers. And the resurgence of cars (mustangs specifically) n the early 90s like racin Jason betwardas mustang revived the turbo movement.


Id like To see a bunch of turbo RVs flying around, that would be great I?d especially like to see a low budget set up put together that?s safe and reliable.
 
Jeff, just curious, what will you do with that extra power in an RV? Is it for better climb? Flying much faster than VNE? Bragging rights? Racing? Towing a trailer? :D

Well for me it would be better climb out personally. My RV is far faster than I need and I’m kind of a
Slow flyer anyway. (Getting old I guess)
I just like HP on tap. Doesn’t mean I’d need to use it. It’s mainly just that you don’t see any aftermarket parts much I understand it’s because of the certified nature of most airplanes but there’s a huge aftermarket potential here for experimentals. Checked out SDS site and that is exactly what I’m
Taking about.
He’s in the right track here there’s LOTS of potential in the aftermarket not being realized here. Maybe because the RV is so good to start with but for guys w earlier built RVs w 150 160 hp engines there’s got to be some bolt on parts that could make some more HP torque. Different ratio rocker arms maybe ? Just getting the conversation going really.
 
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Turbo

My question would be, ?to what end??

I am certainly not opposed to mods but with the 200ktas airframe limit it wouldn?t be speed, it would climb better but then you have cooling issues. Not sure what the gains would be versus the issues...
 
Hot rod

How fast (horsepower)you want to go?
How much money(and time) you have?
= your answer here.
 
Maybe because the RV is so good to start with but for guys w earlier built RVs w 150 160 hp engines there?s got to be some bolt on parts that could make some more HP torque. Different ratio rocker arms maybe ? Just getting the conversation going really.

Another factor is space - there just isn?t a lot of extra room inside the cowl and those who have done turbos on RV have also had to do major work on the cowl.

Search on here for the turbo Rv-6; that builder documented his trials reasonably well and while it worked it was quite of bit of effort over and above the turbo. Either way though I?m sure you?d find it interesting.
 
Where does the fan blow the air when the butterflies close?

Does the turbo continue to spin freely without a blow off valve, and if so how?

Doesn’t that air it’s blowing continue to blow and build up and eventually spin the turbo backwards?

Some interesting assertions here... particularly given the relatively high population of engineers on this forum. Let's explore a little in the interest of physics and fun;

Firstly, a compressor bypass (blow-off valve) is installed on some (not all) turbocharged cars primarily in order to preserve compressor inertia during gear changes and over-run to minimize turbo lag and improve drivability. Airplanes don't change gears, so they don't need a compressor bypass.

What happens to the air when the throttle closes is that it gets compressed. That's all. Remember, with the throttle closed, the exhaust isn't driving the turbine side either.

Turbos don't spin backwards - ever. The compressor slows down yes, but the volume of air in the pipes and intercooler is way too small to accumulate enough energy to stop and reverse the compressor with the throttle momentarily closed.

Consider a vacuum cleaner. What happens to the motor if you put your hand over the intake? Now what happens to the motor if you put your hand over the outlet? That motor loads up and keeps a goin' on my vacuum cleaner.

Just say'in there's physics and then there's - not physics... :p
 
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I was wondering besides more HP what are the best airframe mods for higher top and cruise speeds? How are the ?racers? getting a higher speed on a given fixed propulsion system
 
I was wondering besides more HP what are the best airframe mods for higher top and cruise speeds? How are the ?racers? getting a higher speed on a given fixed propulsion system
 
Piston upgrade

I have read many threads that speak to changing the pistons from say a 7:1 to a 9.5:1 or 10:1. I have been trying to do my due diligence on this. My engine is a an O-320 H2AD that when it was rebuilt the builder had 7:1 pistons put in instead of the stock 9:1 so he could burn 87 octane. To me, this engine is probably about 150 hp now. My question is with this engine, can new, higher compression pistons and rings be installed without any other upgrade and HP increase to say approximately 170hp or more? I don't see me installing a turbocharger!

Cheers
Scott
 
[

So first off I’m happy to meet another turbo guy on here especially one flying a turbo RV. I would really like To see pictures of the set up and how you accomplished that.

so I’ll ask you some questions.

Where does the fan blow the air when the butterflies close?

Does the turbo continue to spin freely without a blow off valve, and if so how?

Doesn’t that air it’s blowing continue to blow and build up and eventually spin the turbo backwards?

Not saying it can’t be done, but
Just because someone has done something it doesn’t make it the best way to do it.
Can you get away without it, possibly That’s a different question.

Lots of guys used draw through systems too but that’s what almost killed the turbo industry. Only the popularity of blow through turbos ion tractor trailers vs superchargers. And the resurgence of cars (mustangs specifically) n the early 90s like racin Jason betwardas mustang revived the turbo movement.

Id like To see a bunch of turbo RVs flying around, that would be great I’d especially like to see a low budget set up put together that’s safe and reliable.

Paddy posted accurate answers to your first questions here about closed throttle turbo operation.

Roush, TRD, Electramotive (Nissan), Porsche, Audi all had winning turbo cars running in Trans Am and IMSA in the '90s. None used BOVs. Hope you're not saying these efforts didn't know what they were doing?

Draw through systems work fine (built and raced those too) but are hard to intercool, given the wet mixture. EFI gives better control of fueling and spark so few people would think of running draw through these days.

You can see some posts here about Lee Ulrich's turbo RV-7 which races at Reno.

As far as custom Lycoming builds go, Lycon and Sky Dynamics have been doing these for many years now. Lots of their stuff has flown at Reno and Red Bull races.

Some vids about Reno turbocharged stuff here on our channel: https://www.youtube.com/channel/UCiyBZlgDHg2GvQfelECCGoQ
 
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I was wondering besides more HP what are the best airframe mods for higher top and cruise speeds? How are the “racers” getting a higher speed on a given fixed propulsion system

Search Dave Anders here. He's got one of the fastest naturally aspirated RVs around. Lots of aero and engine mods to get there.

As some of the thread photos have gone MIA, you can see some info and photos on our "Dave Page" here: http://www.sdsefi.com/dave.htm
 
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I often fly a T182T which I also maintain. Typically out of the initial climb I dial back to 2000 RPM 28" and lean for 1600 TIT ~12.3 GPH. I just keep that power setting after leveling off. Adjust cowl flaps as necessary to keep it cool. Cowl flaps open I typically see 380 CHT in climb. With the cool temps now it will cruise around 340 CHT with the cowl flaps closed. Heat on this airplane is entirely manageable. In reality the turbo simplifies operations as you can run one power setting in climb and cruise.

Would love to have this type of turbo setup in an RV but it would have to be in one of the longer-winged airplanes (-9, -10, etc.) as the high aspect ratio wing works better for higher altitude ops.
 
Mark, Mark, Mark, ;)

Torque alone doesn't make anything go! Torque is a measurement of force only and is but one component required to motivate something. To actually move something, we need to do "work" which is defined as force x distance. And doing that "work" in a finite amount of time requires "power" which is amount of work performed in specific amount of time or work/time. For example, a car's brake can apply force or "torque" to the wheel(s) of a car parked on a hill to keep it from rolling, but it certainly can apply torque while rotating the wheel (work) and it definitely can't rotate the wheel very fast...

Let's try a little though experiment:

Imagine a person with a long torque wrench, say like this 3/4" drive 600 ft-lb model Torque Wrench

With this torque wrench, we can apply up to 600 ft-lbs of torque to something...maybe even a prop hub. How much torque did you say that IO-550-N makes at 2700 RPM and 310 HP?*

OK, so said person (or people) can use that wrench to apply torque to our airplane's prop hub, but to make the plane move we actually have to turn that prop, i.e. do work on it. Of course, even though our torque wrench person is capable of applying a lot of torque with that torque wrench, he's probably going to get tired after trying to turn our propeller more than a few revolutions (doing all that "work") but more importantly, he probably can't turn it very fast while applying all that torque, certainly not 2700 RPM. I.E. he can't make much power.

So you see, torque is not what makes airplanes go!

*So the IO-550-N making 310 hp at 2700 RPM is producing 603 ft-lbs of torque. How much power do we get with 603 ft-lbs of torque at only 2000 RPM? About 230. Is the plane going to go as fast with that same torque at 2000 RPM? Thus, as I said, it's actually power that makes our airplanes go fast.

Skylor

p.s. Horsepower = Torque*RPM/5252. Torque is our measurement of force, "revolution" is our measurement of distance (work) and "per minute" is our "over time". Power = work over time (work/time). The 5252 is simply a unit conversion factor of 550*60/Pi. Part of the reason that it's believed that "torque" is what makes things go is because aircraft engine output figures are very often compared at the same RPM (2700) and thus the torque values of engines of different power are directly comparable...but torque without a measurement of speed (RPM) does not tell us anything about the capability of an engine and how fast it can make an airplane go.

Question:
If the prop was maximized for that 2000 rpm wouldn?t it do the same. Like gearing in a car.
One thing I?ve learned w Pontiacs is they like to be maximized for torque and at a lower RPM can?t build them like a Chevy they won?t live. So if he made the same
Torque at a lower RpM and proped it accordingly like a 308 gear as opposed to a 4.11 gear wouldn?t that make the same amount of work? and therefore propel
The plane the same speed at a lower rpm?
 
How fast (horsepower)you want to go?
How much money(and time) you have?
= your answer here.


Not to sounds cocky but
I beat lots of guys at the track that thought money could win races. Loved doing that more than anything else. 😃👍
My favorite saying is:
Knowledge is power!
 
Not to sounds cocky but
I beat lots of guys at the track that thought money could win races. Loved doing that more than anything else. 😃👍
My favorite saying is:
Knowledge is power!

Great. For zero dollars I can make a stock bug do 0-60 in 2.73 seconds by pitching it off a cliff.

Automotive experience does not automatically translate to aviation. Specifically, the systems used for the highly variable speed automotive engines are simply dead weight for essentially constant speed aviation engines.

Addition of those items probably won't kill you, but your craft will be heavier and more unnecessarily complex than mine at the same engine output.

Here's an idea. How about listening to the advice being given rather than constantly arguing with it. Ask why rather than state yeah but I....
 
I have read many threads that speak to changing the pistons from say a 7:1 to a 9.5:1 or 10:1. I have been trying to do my due diligence on this. My engine is a an O-320 H2AD that when it was rebuilt the builder had 7:1 pistons put in instead of the stock 9:1 so he could burn 87 octane. To me, this engine is probably about 150 hp now. My question is with this engine, can new, higher compression pistons and rings be installed without any other upgrade and HP increase to say approximately 170hp or more? I don't see me installing a turbocharger!

Cheers
Scott

There's more to it than that, no surprise. The biggest issue is wide deck vs narrow deck, and if it's a narrow deck, don't soup it up.

Here's a reference: https://generalaviationnews.com/2009/10/07/ask-paul-wide-deck-vs-narrow-deck-engines/
 
All this talk about more speed, etc, turbos. Anybody every think about flutter? One of my buddies is a DAR for structures and for flutter, and he tells me that flutter excitation comes from indicated airspeed but damping comes from true airspeed... or something like that. If you do even a little research, you can find some gliders, for example, that show redline airspeed (indicated) decreasing with altitude. Van's has posted on this in the past.

I never understood why folks would want to take the wonderful RV handling and then fly straight and level for hours on end. And if you want a faster airplane, go buy one.

All this stuff about world's fastest RV whatever reminds me of that line from a W.C.Fields movie where he's a carnival huckster, inducing folks to come see "the world's largest midget."
 
yep...

"...if you want a faster airplane, go buy one..."

As nice as the RV aircraft are, they aren't the fastest out there. It is great to experiment but if you want a really fast aircraft, it is probably better to look elsewhere than try and make the RV something it is not...

...and you are correct about flutter; it isn't anything to play with...and it doesn't matter how "good" you think you are...

Funny that this would come up again just a day after the anniversary of the Tacoma Narrows Bridge incident...
 
Buying a faster airplane often comes at a steep penalty at the other end of the speed range. I often speed hours on end in a straight line at 200+ k ktas in the Rocket because it's a convenient way to get from point A to point B. I could go a bit faster with a glass bird like a Legacy, but I really don't want to fly an airliner pattern and burn up a mile of runway getting it stopped. I like the fact that the Rocket can easily get in and out of a 2500 strip regardless of loading or DA.

But the point is somewhat valid - going really fast in an RV is not going to happen by throwing a bunch of HP at it. The best bang for the buck is to build light, drag reduction (with specific emphasis on cooling), and optimized engine management (ignition, induction, exhaust). Get it right and you have an RV that will outrun your formation buddies, burn less fuel, and still retain the docile low speed handling RV's are known for.
 
Great. For zero dollars I can make a stock bug do 0-60 in 2.73 seconds by pitching it off a cliff.

Automotive experience does not automatically translate to aviation. Specifically, the systems used for the highly variable speed automotive engines are simply dead weight for essentially constant speed aviation engines.

Addition of those items probably won't kill you, but your craft will be heavier and more unnecessarily complex than mine at the same engine output.

Here's an idea. How about listening to the advice being given rather than constantly arguing with it. Ask why rather than state yeah but I....

Yeah cause cessna and piper never put a turbo charger on an airplane before.
How about contributing something useful

This was supposed to be a fun thread to get information out about options and experimentation not get snarky comments from people.
 
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...and

While I love the experimental part of this hobby and have completed numerous mods, I think that you need to shift your focus a bit, as has been previously posted, to aircraft and away from automobiles.

What works in a car may or may not work in an airplane. Yes, an engine is an engine but there are many other factors to consider in an aircraft. Consider that you car engines are predominantly liquid cooled. Any increase in HP WILL come with an increase in the amount of heat that needs to be rejected...and in an aircraft with an air cooled engine, this can become problematic.

In the RV series of aircraft, you are also limited to Vne on the airframe...unless you want to be a test pilot and push the flutter margins. Again, this has no relative bearing on cars...go as fast as you can.

...and, of course, when things turn bad in an airplane, you can't get out and walk...

I like the discussions, though. Have you read the thread about the guy building up a turbo Honda in an RV? Pretty interesting read...
 
Keep in mind that power or torque do not move airplanes or cars. In airplanes it's applied thrust through the prop; in cars it's tractive force through the tires. A 1000Hp Pontiac Firebird is not going to perform well on a frozen lake with street tires, and neither will a high HP airplane with a mismatched prop. In cars, tractive force is easy to modify for the conditions. You can ditch the Redline tires for sticky drag radials or full on slicks, prep the track with VHT and be assured that you can get all the power to the ground. With RVs the thrust device (the prop) is limited by diameter - strike one. It's also limited by reynolds number (RE) - strike two. Then we have tip speed and Mach which is a combination of prop RPM and aircraft forward speed - strike three. The bottom line is that our a ability to convert additional power to thrust is limited and is subject to diminishing returns.

As a traditional Pontiac street racer since my teen years, I can appreciate the corollary to the Lycoming design - both designs are stout and well adapted to their intended use. I have stomped many a Chevy that had the entire Summit catalog thrown at it with my stock appearing Firebird or GTO.

Like the traditional Pontiac V-8, Lycomings respond well to optimization without a reliability penalty. This is also handled within the limits of available propellers. Once that's done, the airplane is limited by thrust to weight (takeoff and climb) and thrust to drag (speed). There is money to be made to improve these two areas by reducing weight and reducing drag.

The bottom line is that you can have a significantly better performing RV than most of your buddies without even touching the inside of the engine.
 
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Keep in mind that power or torque do not move airplanes or cars. In airplanes it's applied thrust through the prop; in cars it's tractive force through the tires. A 1000Hp Pontiac Firebird is not going to perform well on a frozen lake with street tires, and neither will a high HP airplane with a mismatched prop. In cars, tractive force is easy to modify for the conditions. You can ditch the Redline tires for sticky drag radials or full on slicks, prep the track with VHT and be assured that you can get all the power to the ground. With RVs the thrust device (the prop) is limited by diameter - strike one. It's also limited by reynolds number (RE) - strike two. Then we have tip speed and Mach which is a combination of prop RPM and aircraft forward speed - strike three. The bottom line is that our a ability to convert additional power to thrust is limited and is subject to diminishing returns.

Here it is in a nutshell.

Good job Mike.
 
Keep in mind that power or torque do not move airplanes or cars. In airplanes it's applied thrust through the prop; in cars it's tractive force through the tires. A 1000Hp Pontiac Firebird is not going to perform well on a frozen lake with street tires, and neither will a high HP airplane with a mismatched prop. In cars, tractive force is easy to modify for the conditions. You can ditch the Redline tires for sticky drag radials or full on slicks, prep the track with VHT and be assured that you can get all the power to the ground. With RVs the thrust device (the prop) is limited by diameter - strike one. It's also limited by reynolds number (RE) - strike two. Then we have tip speed and Mach which is a combination of prop RPM and aircraft forward speed - strike three. The bottom line is that our a ability to convert additional power to thrust is limited and is subject to diminishing returns.

As a traditional Pontiac street racer since my teen years, I can appreciate the corollary to the Lycoming design - both designs are stout and well adapted to their intended use. I have stomped many a Chevy that had the entire Summit catalog thrown at it with my stock appearing Firebird or GTO.

Like the traditional Pontiac V-8, Lycomings respond well to optimization without a reliability penalty. This is also handled within the limits of available propellers. Once that's done, the airplane is limited by thrust to weight (takeoff and climb) and thrust to drag (speed). There is money to be made to improve these two areas by reducing weight and reducing drag.

The bottom line is that you can have a significantly better performing RV than most of your buddies without even touching the inside of the engine.


You had me at stomped many a Chevy 😃👍
 
Question:
If the prop was maximized for that 2000 rpm wouldn?t it do the same. Like gearing in a car.
One thing I?ve learned w Pontiacs is they like to be maximized for torque and at a lower RPM can?t build them like a Chevy they won?t live. So if he made the same
Torque at a lower RpM and proped it accordingly like a 308 gear as opposed to a 4.11 gear wouldn?t that make the same amount of work? and therefore propel
The plane the same speed at a lower rpm?

If the engine is still providing 603 ft-lbs of torque at 2000 RPM's you are still going to be down 80 horsepower over an engine producing 603 ft-lbs of torque at 2700 RPM. You most likely can't make up for that large a difference in power with a more efficient prop.

Skylor
 
Maybe we are looking on this the wrong way & Turbo69bird is on to something here. A High Output light weight engine, maybe driving a split drive train to twin props mounted on a high tilting wing for the new RV-15 VTOL model.
We can dream!:D
Oops! Wrong thread.
 
OMG...

A single engine driving TWO props through a drive train?

My God, man...where is your redundancy? It's a single point failure waiting to happen!:rolleyes::D
 
Thanks for the discussion. Back to the airframe. So cooling drag is worth the focus? General rigging?
Great to learn from you guys.
 
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