TSwezey? - Page 4

TSwezey · #31 03-06-2008, 03:48 PM

Ross-I forgot to congratulate you on getting the engine on and on gear. I saw it on the home page and I couldn't find the thread!

rv6ejguy · #32 03-06-2008, 05:42 PM

Quote:

Originally Posted by TSwezey

Ross-I forgot to congratulate you on getting the engine on and on gear. I saw it on the home page and I couldn't find the thread!

Thanks. It's been a long time coming and yes, I'm still way behind you- just joshin'.

Great paint job BTW!

TSwezey · #33 03-06-2008, 09:09 PM

Quote:

Originally Posted by rv6ejguy

Thanks. It's been a long time coming and yes, I'm still way behind you- just joshin'.Great paint job BTW!

I know! .

Rotary10-RV · #34 03-07-2008, 12:14 AM

Quote:

Originally Posted by Mike S

A question for you guys---------

There was a guy with a SeaBee powered by a Chevy V8, got a lot of press a couple of years ago, cover of EAA mag IIRC.

Anyone remember if this was a Vesta setup, if not, who??

Thanks.

Mike,
I think Ross beat me to the punch. The SeeBee unit was not Vesta. They have gotten some good hours out of the setup that was used. Heavy sucker with the long prop shaft for the high mounted pusher. Something like 69 pounds if memory serves. Though I would rather have heavy than unreliable. There have been several different Hi-VO chain PSRUs. The Hi-Vo is a strong unit, and can be had in many widths. There are two items of concern when designing these drives. First the chain runs on the sprocket like a gear. This is good (strong and quiet) and bad. The chains usually recomend an oil spray. Some people use a submerged system, but all the oil can get picked up and thrown to the sides of the casing, so a pressure feed of some kind is a good idea. Second the sprockets need to be steel faced for wear reasons. This means the sprocket set for 300 HP is usually around 35 pounds by itself. so the PSRU will usually be fairly heavy, at least 50 pounds for 200-300 HP. The last item is related to the sprocket/chain system in general. For a high reduction ratio the sprocket simply MUST be fairly far apart resulting in a large offset. On a V8 engine where you want to raise the thrust line or conversely lower the crankshaft the big offset is an advantage. If you are building for a compact engine, or a horizontally opposed engine like a Subaru the large offset is more of a bother than a help. Just some FYI.
Bill Jepson

TSwezey · #35 03-07-2008, 04:45 AM

Bill,
You right about the weight of the PSRU. It is not light. The weight really doesn't bother me too much. I would rather have heavy and strong than light and weak. I think my PSRU is easily 60 lbs probably a little more. The Robinson conversion is really a great product. I believe Jason Day (Vesta) will get his PSRU to work well. It will probably take some more minor modifications.

Rotary10-RV · #36 03-07-2008, 09:22 AM

Quote:

Originally Posted by TSwezey

Bill,
You right about the weight of the PSRU. It is not light. The weight really doesn't bother me too much. I would rather have heavy and strong than light and weak. I think my PSRU is easily 60 lbs probably a little more. The Robinson conversion is really a great product. I believe Jason Day (Vesta) will get his PSRU to work well. It will probably take some more minor modifications.

Todd,
I am sure that Jason has the intelligence to make the product work. I made some comments about the setup some time back. We argued about the needs for under-cowl cooling for a V8. Jason and I went back and forth in the forum. Jason and I then took it to PM as I didn't want to harm his business. The messages sent privately convinced me that Jason understands what is needed to design a suitable system. The dual side exit with two large radiators is one of the setups I looked at, (and I'm still considering), for my rotary install. Jason and I worked it out and I encouraged him to post NEWER photos on the web site. (The original photos were what I was advising someone against, but he had already upgraded the radiators by then.) He needs to get some on aircraft photos to post. Your plane will be a great sales tool once flying. If you have seen any of my posts in the past you will know that I am a big supporter of alternate engines. My concern is that the providers of packages actually follow through on their promises. Jason seems to be doing that, and showing concern for servicing the customer after the sale, which is VERY important. The guys engineering new PRSUs need to understand that just a by-the-book overdesign rarely is tough enough because there are so many unknowns that are very hard to plan for.
A little side comment so you understand what I'm talking about. As a youngster I took a tecnical training course at Kawasaki. (I was 17) The course was excellent with two great instructors, who devised some truly diabolical final tests. When folks taking the course complained they replied, "We give you the toughest tests we can think of because in real life you will find things are ALWAYS WORSE!" The point? THEY WERE RIGHT!
Bill Jepson

DanH · #37 03-07-2008, 11:15 AM

Was it Vesta that originally incorporated a sprag clutch in the design? If not, anybody remember a V8 system that did?

TSwezey · #38 03-07-2008, 01:37 PM

Geared Drives uses a clutch. I think it is Geareddrives.com.

rv6ejguy · #39 03-07-2008, 03:10 PM

Quote:

Originally Posted by Rotary10-RV

My concern is that the providers of packages actually follow through on their promises. Jason seems to be doing that, and showing concern for servicing the customer after the sale, which is VERY important. The guys engineering new PRSUs need to understand that just a by-the-book overdesign rarely is tough enough because there are so many unknowns that are very hard to plan for.

Bill Jepson

Excellent post Bill. I have designed things using the engineering data say on a bearing with a 3X fudge factor on top of that even and guess what? It doesn't last sometimes. Many times there are unknown variables that we don't uncover until we build and run/test a design for a while. The proof is indeed in the pudding as your post heading states.

I'm all for applying the best analytical methods available to us in the design stage and then following up with instrumented testing but in the end, if it doesn't last for the design period, it is really no good.

If any of the alternate guys need to do more of something, it is in all 3 areas. I still don't understand why all vendors don't have their own test plane to do testing in the true application. I know that has helped our aviation sales immeasurably.

I am very happy to see Jason do what he says he will on his site for his customers but if I can offer one last piece of advice, it is best not to predict how well something will work until you do it and test if for a long time. Projected TBOs on new engines always make me laugh.

I was as guilty as many others thinking I was a pretty smart guy when it came to engines and related things and it would work really well. My real education started when I actually screwed the whole thing together and started to fly it. I couldn't have been more wrong about the first point. I know a lot more now but I'm sure I'll learn many more things on the next plane.

Todd, we are all following your project with great interest and I hope to have that fly off sometime with you.

gmcjetpilot · #40 03-07-2008, 04:08 PM

Quote:

Originally Posted by rv6ejguy

I have designed things using the engineering data say on a bearing with a 3X fudge factor on top of that even and guess what? It doesn't last sometimes. Many times there are unknown variables that we don't uncover until we build and run/test a design for a while. The proof is indeed in the pudding as your post heading states.

Ross, I have some questions on you RV-10 (and RV-6A) project'(s). I started a new thread, mostly about the Marcotte drive v. Eggies Gen III. Thanks George

New Thread: "Questions on Ross's EG33 Subie RV-10, Marcotte Drive" LINK