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Windshield type (shape)

Freemasm

Well Known Member
What are the advantages/disadvantages of the Speed Slope Windshield versus standard shape? (not talking sliders vs. floppers).

Speed
Visibility
Ease of construction
Sealing
Access

Any/all opinions are appreciated.
 
What are the advantages/disadvantages of the Speed Slope Windshield versus standard shape? (not talking sliders vs. floppers).

Speed
Visibility
Ease of construction
Sealing
Access

Any/all opinions are appreciated.

One looks stunningly sharp (in more way than one, IMO.) Other than that, I would think very little. The optics may be a little different. Would be interested to hear from someone who has flown behind both.
 
Plus side:
. it’s gotta be faster. One is a sharp change to direction of flow, the other is very gradual, otherwise, we wouldn’t have wheel pants.
. It looks better, no question. Everybody will see “speed”.

Negative side:
optics cant be as good. Take your sunglasses, put them at a very steep angle to your eyes and look through them, tell me what you see. A little distorted, right?
But who cares..... you’re going faster.
 
One other thing to consider is the consistency of thickness with a flat wrap. Blown bubbles can get pretty thin in areas.

As for speed, I noticed no difference when I did the -8, so I expect no difference when I do the Rocket. I'm doing it mostly for birdstrike protection.
 
One negative that most people don't think about...the sharp break at the junction between the canopy bubble and the "speed sloped" windshield can create a tripping point for airflow, which becomes separated and creates drag, costing speed and creating more wind noise.

Vought discovered this with the F4U Corsair...the first models with the greenhouse canopies had the sharp break, and when Vought went to the blown "Malcolm" canopy design they discovered through wind tunnel testing that the airflow around the canopy was smoother and more laminar because the juncture between the windshield and the canopy was more in the same plane...it "flowed" better. Test pilot reports at the time claimed they picked up 10 knots from the canopy change, and the cockpit seemed quieter. It must be true because we all know that pilots never exaggerate... :D

On the Rockets this break doesn't appear to be so bad, but I've seen a couple of 8's that were sharp enough to make me wonder. Best of luck whichever way you choose!
 
I PROMISE!! Well, maybe...

The Speed Slope windshield adds at minimum..uh...better (small) bird strike protection. I was gonna add 5KT too, but that is not so. If you want to do it better, ask Jeff to make you one that is 1/4”-5/16” thick. It might bounce a medium sized bird if it’s that thick. 3/8” thick might actually bounce a fair sized bird, but that thickness might not fit up so well..

Airplane Plastics makes VERY good parts - there is no discernible sight distortion when looking thru the Speed Slope w/s. Installing that part is no extra work when compared to the std plexi.

The composite fairing blends the windshield to the aft section - I doubt there is discernible drag at that point. I could do a flight to see - I sure can’t hear anything.

Jeff has come up with a slightly higher bubble too - that would ease the w/s to the aft shape if you are doing the whole plexi...he also has a U/V stop plexi that is very nice to fly under - making the process of changing the whole canopy worth the trouble.
 
I asked Jeff some time ago to blow me a bubble with a steeper front windscreen and that's probably what Mark is referring to. I didn't like the "bluntness" of the standard canopy nor do I like the look of the flat wrap (personal preference). I'd post a pic but it looks like too much hassle .... but the bubble came out much to my liking.
 
I asked Jeff some time ago to blow me a bubble with a steeper front windscreen and that's probably what Mark is referring to. I didn't like the "bluntness" of the standard canopy nor do I like the look of the flat wrap (personal preference). I'd post a pic but it looks like too much hassle .... but the bubble came out much to my liking.

Lary, would love to see a pic. Just use the little paperclip. It's a very easy process now - takes 15 seconds. No host required.
 

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...otherwise, we wouldn’t have wheel pants.

Wheel pants have more to do with the trailing edge than the leading edge. Unless you're going supersonic, pointy noses / leading edges do not do much to reduce drag (the slight drop in pressure drag is pretty much canceled out by the increase in viscous drag from the added surface area... Heck, look at the nose of most Airbus airplanes), but a teardropped trailing edge prevents separation and thus reduces pressure drag by a lot while only increasing viscous drag a little bit.

I would bet that the benefit of the Speed Slope windshield is mostly aesthetic. Not that there's anything wrong with that!

And, as Mark and Michael pointed out, it might be a little more bird-resistant, I wouldn't be surprised.
 
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pics

Here goes my try at putting pics in. There are 2 pics of Jeff's canopy with the extended steeper front and one with a blank "speed slope" set in place. Since these pics I have trimmed the canopy more and moved it forward.
 

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Thanks Larry

Thanks for the pix you sent through email. I'm contrary to the opinion expressed here by most; but, I've gotta say that "custom" canopy shape looks quite nice. The lines are very complimentary to the rest of the airframe. Assuming there's no aero or acoustical downside, nice choice.
 
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