Speed difference trigear vs. taildragger

GSchuld · #1 02-05-2009, 10:54 PM

Is there a general consensus as to how much of a speed penalty is assumed for a trigear over an otherwise identical setup taildragger? For example a 6 and a 6A, same 180hp engine, same prop, etc. with each set of gear given a thorough aerodynamic treatment(good quality wheel pants, gearleg fairings, intersection fairings, etc)

George

Greg Arehart · #2 02-05-2009, 11:10 PM

This stuff is on the Vans website. Generally the difference is not much - a couple knots at most as I recall.

greg

RatMan · #3 02-05-2009, 11:14 PM

About 2 MPH.

Check out this page http://vansaircraft.com/public/rv-6per.htm or any of the other "performance" pages at Vans.

Hawkeye7A · #4 02-06-2009, 12:09 AM

Can't comment on the tail vs. tri difference. I did however, see an increase of 13 knots by adding the gear leg and wheel fairings.

Bob Axsom · #5 02-06-2009, 01:40 AM

Van's lists a 2 knot advantage for the tail dragger given the same power source. However, when you say "with each set of gear given a thorough aerodynamic treatment (good quality wheel pants, gearleg fairings, intersection fairings, etc)" you get into a need to compare things that are not assigned factory numbers. The best source for that is the complete set of race results for all of the races sanctioned by the Sport Air Racing League during its first two years of existance. These can be viewed at the www.sportairrace.org website. On the home page there are links for the 2007 season and 2008 season results. At each of these locations there is a link to the results for every race completed. The specific type may not be listed for every type of RV in every race (it seems I saw an example of that) but if there are some that are not shown that you are interested in I can look up the omitted types for you. They have two classes just for RVs with 320 cu. in. (RV Red) and 360 cu. in. (RV Blue) engines. Some RVs have other sizes of engines and they race with other comparably powered and configured aircraft. I know of two serious competitors in the RV Blue Class Race #26 (Rv-6) and Race #71 (RV-6A) that have each beaten the other in head to head competition. With no change to the stock O-360-A1A engine with 8.5:1 pistons or old style 72" 7666 bladed Hartzell prop I have added 12 knots to my RV-6A's top speed with aerodynamic cleanup alone (including cooling drag) and there is more there to be had. History shows that the RV-8 is the fastest of the whole RV breed - especially John Huft's Race #18. How fast your RV will go depends on how you modify it - the location of the "little wheel" is a small part of the raw material you have to work with. One of my largest gains in speed was achieved by fabricating a subfairing for the nose wheel fairing which exceeded the two knot advantage Van's data gives to the comparable taildragger.

Bob Axsom

JonJay · #6 02-06-2009, 08:25 AM

....sitting on the ground! They just look fast dont they?

Bob Axsom · #7 02-06-2009, 09:23 AM

Back in the day when the Curtis P-40 was king of the AVG Flying Tiger media blitz I always thought the Bell P-39 looked faster. With a little work you can easily overcome the two knot difference in the stock configurations but the road to success is not simple and the ultimate speed of each type is unknown to those of us who are still alive.

Bob Axsom

JonJay · #8 02-06-2009, 12:41 PM

Quote:

Originally Posted by Bob Axsom

Back in the day when the Curtis P-40 was king of the AVG Flying Tiger media blitz I always thought the Bell P-39 looked faster. With a little work you can easily overcome the two knot difference in the stock configurations but the road to success is not simple and the ultimate speed of each type is unknown to those of us who are still alive.

Bob Axsom

Come on Bob, EVERYBODY knows that Tailwheel, fully Primed, Slider, C/S, Injected, Alternate Air, Manual Trim, Van's Cooler, aircraft are the fastest.

(nobody knows speed like you, so I wont argue, even just sitting on the ground)