altruistic
Member
Can anyone give me a comparison of the behaviour in flight of a fastback RV8 vs the conventional canopy. It certainly looks better (subjective) but does it stall differently or fly faster?
...........Probably won't make any difference in speed or stall characteristics, UNLESS the plane is built in Texas. (or maybe Oklahoma)
Probably won't make any difference in speed or stall characteristics, UNLESS the plane is built in Texas. (or maybe Oklahoma)
I've often thought that the canopy profile and position on the -8 may be a contributing factor to the unusual stick forces experienced on the -8 at low speed and increasing AOA (landing). There have been past discussions and some conclusions that the cause of this phenomenon was the position of the gear leg intersection at the fuselage. While I don't disagree, I'm not at all certain it's the major cause.
The -8 fast back could well be the platform to easily prove or disprove my theory and possibly contribute to a fix for those of us 'not so fortunate' owners of a standard model. A simple comparison could be accomplished in a short period of time... same pilot (well qualified and experienced in the -8 standard model), 2-aircraft, one standard and one fast back balanced to same CG (tests at fwd, mid and aft CG), a few air and landing test regimens, and some cool ones afterward to complete the debrief.
At the very least, the test would be a great excuse to go fly... Any additional thoughts? Anyone up to the task?
The 8 VS 8A comparison would be valid as far as the gear question goes, but the fuselage question would still remain unanswered until a fastback A model were built.
I strongly believe in fuselage lift. Bellanca believed in it and so did Burnelli.
Zivi Nadivi flew an F-15 without the right wing for 10 miles and ended with a successful landing. (at 260 knots)
So I find it possible that the shape of the back of my stock 'old style' RV-8 canopy could cause flow characteristics that effect the feel of the tail plane.
I'm not planning to do anything about it just yet. I'm more interested in the other end of my plane.
Yes, I was referring to the neutral to negative stick force gradient when at aft c.g., and I agree with almost everything that you have said.
You stated "the -4 has roughly the same canopy lines, so I doubt that the canopy-aft fuselage shape is a contributing factor".
You may well be correct, and my observation may be the result of my age, 8 year old glasses, and no engineering background. Some time ago however I had the opportunity to stack a friend's -4 and my -8 together in the hangar and my visual observation at that time was that the -8 canopy was considerably taller, somewhat wider, and that the rear profile differed slightly. I didn't take measurements, and of course my observation was without the benefit of any engineering background or data... it just appeared that it may be a contributing factor. I'm just a lazy opportunist searching for answers.
Anyone up to the task?
I'd love to, except I refuse to make my -8 a fast back since I'm the only person in the world that finds them ugly, try-hard and me-too. (no disrespect intended).
I'd love to, except I refuse to make my -8 a fast back since I'm the only person in the world that finds them ugly, try-hard and me-too. (no disrespect intended).
In the context of speed, two advantages for the tip-over; better sealing at the canopy perimeter (reduced leakage drag) and reduced canopy drag due to the one-piece bubble. Raymer suggests canopy form factor drag is increased by 40% with a seamed two-piece canopy.
However, speed considerations pale compared to the Missus Factor. Most of us are happily paired with lovely ladies of a certain age. A lot of those ladies have a very practical problem with RV entry and exit; it's hard to be graceful when there's nothing good to grab. The relocated roll bar assembly is a huge handhold.
As one who thinks Fastback -4's and -8's DO look much better, mostly becausew they get rid of that bulbuous giant canopy look on the -8 especially,
Also, I believe your statement "In my opinion (the one that counts), I have the best looking one by far." summarizes the standard vs fastback discussion very appropriately.Scott - that is one of the best, most objective write-ups on the topic I've ever seen - thanks for taking the time!
Probably won't make any difference in speed or stall characteristics, UNLESS the plane is built in Texas. (or maybe Oklahoma)