How would you win the Sport Racing class/why am I wrong?

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Toobuilder

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I'm not super familiar with the canard variants that are out there but they "seem" like the a easiest platform for integrating a big power V-8. Plenty of fuselage/wing cross section to hide the engine within, and a now superfluous rear passenger seat to hold "stuff" that goes with keeping 1500 alive for 10 minutes (ADI tank, etc). With that premise, I'm guessing the Berkut is about the strongest and cleanest (happy to be corrected if not the case). So what would it take to get a Burkut to 450 down the straights? Is the structure even capable of those speeds, and what level of HP would be needed?
 

rv6ejguy

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The GP-5 was turning in some very good speeds on the hp it had in 2012 (around 525-530hp according to EPI), showing it had less drag than the side by side planes. With the 850-900 ish hp the big boys have now, that would mean 420-430 mph lap speeds- so about 10-20 mph faster than LaVelle or Findlay have run on this course.
 

mcrae0104

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It is interesting that Pereira stated that the spar was originally constructed without any splices along the length of the caps, and did not recall making any repairs to the caps when he repaired the wing following the 2012 gear collapse damage. It appears that either:
  • His memory of the original construction was incorrect, and either the wing spar was faulty from the beginning, just waiting to fail, or the new speed of the re-engined aircraft somehow exacerbated the problem,
-or-​
  • He didn’t want to fess up to an improper repair that he had performed.

Either way, the failure of the joint on the glue line (not in the wood grain) is troubling. I would like to know what type of adhesive was used and why it failed (improper selection, improper mixing, improper application?) but I doubt we will ever have that information.

Here is a GP-4 wing, which has the same split spar caps as described in the NTSB report. It is an interesting method of tailoring the caps while maintaining some minimum thickness to the cap and keeping the fwd and aft faces of the spar parallel.
1633189477928.jpeg
 
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Riggerrob

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Has anyone raced with two engines coupled end to end?
I am working now on coupling two engines in my experimental shop.
A few have tried coupling two engines together, but none entered production.
The closest were the experimental, high speed airplanes built by Bugatti and Heinkel. Both had a pair of engines amidships, then drive-shafts forward to the nose where they drove a pair of counter-rotating propellers. The dirveshafts widened the cockpit, but also allowed plenty of glass along the sides and the cockpit ended up much shallower with great visibility.
If you are going to the trouble of installing drive shaft, I would use them to my advantage in a pusher configuration. Most pushers need driveshafts to mount propellers aft of the wing, but engines amid-ships for balance.

As Toobuilder suggested, a Rutan-style canard (e.g. Berkut) would allow mounting the engine mass very close to the main spar - for shorter load-paths. You still need major sweep in the main wing for balance and mounting rudders far enough aft to provide yaw control.
If you want a twin, you would be wise to start with Burt Rutan's Defiant push-me-pull-you, mind you Defiant would only provide the concept as any racer would fly twin as fast as Defiant's Vne. The race configuration would have lower aspect ratio, larger control surfaces and a far stronger airframe.
 

billyvray

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I really wish there was resurgence in the unlimited space that truly inspired innovation and experimentation.
For me- I’d like to see a couple of LS V8s coupled end to end for some stupide horsepower.
 

Voidhawk9

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I'm not super familiar with the canard variants that are out there but they "seem" like the a easiest platform for integrating a big power V-8. Plenty of fuselage/wing cross section to hide the engine within, and a now superfluous rear passenger seat to hold "stuff" that goes with keeping 1500 alive for 10 minutes (ADI tank, etc). With that premise, I'm guessing the Berkut is about the strongest and cleanest (happy to be corrected if not the case). So what would it take to get a Burkut to 450 down the straights? Is the structure even capable of those speeds, and what level of HP would be needed?
I'm working on doing something similar but with a Cozy basis, and not for racing (no ADI or turbo and compromises for practicality).
The Berkut aerodynamics are tweaked slightly from a Long-Ez (as is the Cozy, but in a different direction), which itself was designed to run around with an O-235. So the wing isn't really ideal for really high speeds, though structurally has margin to a point. My simulations suggest the design would need some major aero changes to effectively go much faster than they already do. Klaus Savier is doing just this with his heavily modified Long-Ez.
My Cozy derivative seeks to make aerodynamic changes to enable higher speeds and greater efficiency - new airfoils optimized for laminar flow and higher cruise speed, ducted cooling, lots of revised aero throughout. And an LS3 on the tail. But it's slow progress on development and construction as other things are higher priority at this stage.
 

rv6ejguy

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The Fiat AS6 V-24 was derived from the concept of two V12 engines joined together, though sharing a common crankcase so not really 2 separate engines though essentially so in every other way. Pretty amazing piece of engineering for the mid '30s. I've always thought the Italians did a fantastic job with the MC72 float plane. The record has never been beaten. FIAT AS.6 Aircraft Engine (for the MC.72)
 

BBerson

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Hmmm, that Fiat AS.6 with uncoupled crankshafts isn't what I am doing, but might be an option for Reno racing. It probably isn't practical to direct couple crankshaft together that long because of torsional vibration.
 
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speedracer

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Gary Spencer has a Ford V8 powered Long EZ and runs it direct drive. He was a regular at Shirl Dicky's R.A.C.E. (Rutan and composite enthusiasts) air races. I beat up on him for two years with my 170 HP angle valve 290 powered Long EZ. He could only average about 220 MPH around the 120 mile triangles and I could do 230. The third year he did SOMETHING over the winter and just turned into a dot out on the race course running around 250 MPH. BTW, those races ran for 22 years (7 classes) with a perfect safety record which is pretty remarkable.
 

tallank

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Cut 20" out of the center of a Lancair or Glasair, then glue the two halves back together. I have some gap-filling CA glue somewhere around here, but sadly, I'm fresh out of Glasairs.



Bingo! I have always thought that clipping wing span is a terrible way to cut drag for a racing plane, yet it's done all the time. I understand that Sea Furies actually turn the pylons slower with less span, despite the reduced wetted area. Some racers in the past have mated other wings to an existing fuselage (e.g. Miss Ashley or others); for all that effort, building a longer-span wing of the original area (or less) would prove more effective. Racing at higher load factors demands lower span loading (or whatever tricks you have in your bag to reduce induced drag), not simply reduced wing area. Perhaps now that we are past "peak warbird," this idea will occur to some enterprising designer/builder/racer.



The GP-5 used my favorite composite material... :)
This fact is right in front of everybody's eyes at Reno, Formula 1s. The old Cassutts (sic?) had thin short wings. Then came along Nemesis with its thick long wings and it was 50 mph faster that all the others. A lot of the Formula 1s now have thicker longer wings. Sailplanes knew this decades ago and now look at all of the newer airliners.
 

rv6ejguy

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This fact is right in front of everybody's eyes at Reno, Formula 1s. The old Cassutts (sic?) had thin short wings. Then came along Nemesis with its thick long wings and it was 50 mph faster that all the others. A lot of the Formula 1s now have thicker longer wings. Sailplanes knew this decades ago and now look at all of the newer airliners.
I think you should check your facts here. Ray Cote in Shoestring did 254 mph back in 1980. Jon Sharp was only marginally faster nearly 2 decades later in Nemesis, not 50 mph... Ray would have beaten the entire F1 field in 2021 with his 1980 speed.
 

Tiger Tim

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I guess one thing to consider is what if you did show up for Sport in something that went 50+mph faster than anything else in the field? Would you kill the sport or would they just kick you out?

I guess you’d have the option to sand bag it down into the range of the average of the faster speeds in qualifying then on race day just do better than second place...
 

rv6ejguy

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Not as long as Rust, Findlay, Lavelle and Eldridge can breathe.
Well if you beat them by 50 mph, they'd be forced to spend a lot of money to change equipment. Nothing much has changed in Sport Class in the last 15 years. Sharp, Findlay and LaVelle have all turned 410ish mph laps with turbocharged Lyconental power running 90-100 inches in side by side designs. This recipe is pretty much tapped out. You'll see only incremental speeds increases with these setups. A smaller, narrower airframe will net 10-20 more mph but the main gains will be stepping away from the mechanically and thermally challenged Lyconentals to liquid cooled, geared automotive based engines which are larger, stronger and and turn double the rpms. There is the possibility to double or even triple the current hp levels. This will bring speeds up to where conventional propellers and unswept wings don't work well anymore due to mach effects.

I predict few will spend this kind of money. Andy and Jeff are headed to Unlimited now. Not sure if they will be running Sport class any more. Jeff certainly doesn't have anything to prove any more. How many times do you have to win a class to prove you are awesome?
 
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Victor Bravo

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I think you should check your facts here. Ray Cote in Shoestring did 254 mph back in 1980. Jon Sharp was only marginally faster nearly 2 decades later in Nemesis, not 50 mph... Ray would have beaten the entire F1 field in 2021 with his 1980 speed.
The stock Shoestring had a higher aspect ratio wing than the stock Cassutt. The basic Shoestring fuselage is longer than the Cassutt, so as both airplanes were fitted with higher AR wings, the Shoestring fuselage could always be fitted with a little longer wing than the Cassutt. So they always turned better. Dusty Dowd in a stock-span "Hershey bar" Cassutt was within a few MPH of Cote, which was an astounding achievement with a less refined airframe shape.

Anybody who can just out and out win Reno, while flying in a clown suit and clown makeup, has certainly earned the status of a legend :)

The metal propellers used in F-1 were outlawed after one or two high-profile incidents, and the wood/composite props never caught up.

Jon Sharp's airplane was certainly cleaner than either of Ray's Shoestrings, but I'm pretty sure the sneaky old codger had a trick or two up his sleeve and little more piloting experience. He had access to a lot of talent too... he had significant factory assistance from Continental back in the day, so one would have to assume his engine was pretty healthy. And remember Cote was at Ryan Aircraft in san Diego, so he had access to pretty experienced and high-end aero guys. A Ryan aero guy (Doug Fronius) designed the only F-1 racer with the clear potential to beat the Shoestring and Nemesis, but the airplane crashed on the test flight because of a flutter incident.

Ray used to wrap the bare copper core of the ignition lead wires around the tips of the spark plugs to get a little hotter spark.

Jon had a couple of secret weapons too, a fellow named Don Sanford (engine and ignition specialist) and Steve Ericson (a very skilled aero guy who worked with Jon at Skunk Works).

Spinning a polished, thinned aluminum propeller at 4500 RPM is going to be hard to beat even with the solid carbon props that Jon's guy built.
 
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