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  #11  
Old 01-25-2010, 07:05 PM
GeeBeeFan GeeBeeFan is offline
 
Join Date: Dec 2009
Location: CHA
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Quote:
Originally Posted by Toobuilder View Post
What is the mission of this airplane? Once you can articulate this and then define the individual requirements of the mission, you then find (or design) the airplane to match. Don't find the airplane first then try "back into" the requirements.
The primary mission is to race at this plane at Reno. Secondarily I would like to participate in some cross country races IF I can work in enough fuel capacity. I would like to think I can build an all metal airplane to keep up with the NXT but those have been turning some incredibly impressive numbers lately.

Honestly this has been a pet project of mine for many years and as you can tell its been very slow progress, real life keeps getting in the way. I am an experimenter and tinkerer in my spare time so just building it will be reward enough, if it actually wins something that will be icing on the cake.

I've been looking into the RV line because if I can share parts it will save me some work but if I have to start from scratch then so be it. I dont know if you guys are interested but here is a dreaming sketch I did based on the 3-view in the preview plans. It should be easy to see how far out I am thinking with this one. The canopy is too small but the RV cues are still there, the fin, wing, seat placement and length are all stock -4


Thanks for the help guys. I'll still be lingering around here for a while, perhaps you'll spot this thing at airventure sometime soon.
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  #12  
Old 01-25-2010, 08:00 PM
lancef53 lancef53 is offline
 
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That looks awesome--kinda like a mini P-51 with the scoop.

Keep us posted, lots of people said it wouldn't work to Orville and Wilbur too
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  #13  
Old 01-25-2010, 08:04 PM
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n5lp n5lp is offline
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Quote:
Originally Posted by GeeBeeFan View Post
...
...


Well the tail is different.
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  #14  
Old 01-25-2010, 08:08 PM
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N941WR N941WR is offline
 
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Good idea, keep going.

Try reasearching the NACA 2300 series airfoil most of the RV's use. I have heard they hit an aerodynamic brick wall around 200 mph. This could be true or total BS, I don't really know.

Free of the RV wing profile, you can still use the Spars, and other parts for your project.

One other challange you will have in the P-51RV you penned is getting the water and oil lines to the cooling doghouse without risking the life of the pilot. If I were to fly a plane (Other than a real war bird) with that type of radiator set up, I would want to make sure I don't get boiled if a line broke in flight or after a hard landing.

Keep drawing, soon it will be time to pound aluminum.

BTW, Lycoming makes an IO-720 400 HP eight cylinder engine. That might be a good starting point.
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RV-9 (Yes, it's a dragon tail)
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  #15  
Old 01-25-2010, 08:10 PM
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N941WR N941WR is offline
 
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Quote:
Originally Posted by n5lp View Post


Well the tail is different.
Larry, I have always wondered why the left the doghouse on the bottom of that plane. After all, the engine doesn't need it.
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Bill R.
RV-9 (Yes, it's a dragon tail)
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Build the plane you want, not the plane others want you to build!
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www.repucci.com/bill/baf.html
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  #16  
Old 01-25-2010, 08:53 PM
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Toobuilder Toobuilder is offline
 
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Quote:
Originally Posted by GeeBeeFan View Post
The primary mission is to race at this plane at Reno. Secondarily I would like to participate in some cross country races IF I can work in enough fuel capacity...
OK, if you want to win against the fast glass, you are going to have one heck of a time with the surface finish that a riveted aluminum structure provides. RV's are built the way they are because it is inexpensive, easy, and forgiving of mistakes. The fact that they are relatively fast is icing on the cake, but their mission is to be a sport airplane, not a racer.

I was very much in the same boat as you not too long ago, but my mission was not to race (but high speed was a key). I wanted to use some RV components to save time, but in the end, if you want a thoroughbred, you are going to have to optimize everything. Keep in mind that the HR is an adaptation of the RV-4, which is from the RV-3, which in turn came from a modified Stitts Playboy. The point is, hanging a V8 on the nose of a Rocket might make it go faster, but at what expense, and will it be fast enough? BTW, a pumped up 540 could make 400+ HP pretty easily also, and be a whole lot easier.

The point of writing all this is not to discourage, but to point out that the HR is just about as fast as it's going to go right now. Without some serious aero work, even 1000 HP will not help a lot. BTW, just as a point of reference, I once read that 1000 HP is the figure that would be required to drag a Cessna 172 to 200 MPH in level flight.

I think you need to decide what your specific goals are, then decide what kind of equipment will meet that need. If you want to beat Jon Sharp within the Supersport rules, you will quickly see that a metal airplane like the HR is not going to do it. I’d suggest doing some research on the Arnold AR-5 as an example of near aerodynamic perfection. It’s a good lesson in what makes stuff go fast - then go from there.

Best of luck
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  #17  
Old 01-26-2010, 12:25 AM
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Dangerous Dan Dangerous Dan is offline
 
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Default V8 power for V8 fun!

Gee Bee Fan,

I recall there are kit mustangs about 1/3 scale that use the V8 engines. If using a V8 is your goal these kits or plans might have much of the design work for engine mounting and under fusealage radiator worked out.

I believe when the newest F1 rocket kits are available its higher VNE and new wing could give you the other half of parts you need to build an Airplane that would make Henry Ford sit up and take notice.

Yeah that is it! use the modified P-51 fueslage and new F1 wings and empanage.

Go for it!
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Wanna be: RV-4 then Rocket
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  #18  
Old 01-26-2010, 04:56 AM
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Michael White Michael White is offline
 
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Location: Cartersville, Georgia KVPC
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Quote:
Originally Posted by N941WR View Post
Larry, I have always wondered why the left the doghouse on the bottom of that plane. After all, the engine doesn't need it.
Bill,
The Legend was originally designed around a liquid cooled V8, hence the radiator scoop. IIRC, there were problems with the V8...don't remember exactly if they were cooling issues or reliability issues...that led to the installation of the turbine. Most Legend builders have either reduced the size of the scoop, faired it over or removed it entirely as it is no longer needed.

Best,
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  #19  
Old 01-26-2010, 05:02 AM
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Jeff Brenhaug Jeff Brenhaug is offline
 
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GBF,
In the relentless quest for speed I have toyed with many ideas to make the HR3 even faster than it is already.
The wing is the limiting factor and so I have put my name on Mark Fredericks list to be one of the first to purchase his new F1 kit with the composite wing to satisfy my need for a 2-place aircraft.
Meanwhile, I still look at ways of increasing the speed and have looked into re-winging the HR3.
You can go here and see that this gentleman used a Mustang II kit for his project with some impressive numbers coming from an O-360.
http://www.nexusmustang.com/
I'm looking into using this same wing for the HR3, with some mods of course.

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  #20  
Old 01-26-2010, 08:42 AM
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F1Boss F1Boss is offline
 
Join Date: Aug 2006
Location: Taylor Texas
Posts: 811
Default Yes, to a point..

GBF:

Yes, the structure is strong enough to take the added power and weight...IF...you agree to lower G limits. While this step is not quite as large as putting the 540 on an -8, the stock airframe with a heavier engine will be good for some percentage of design load. Don't forget propeller loads in your calculations!

As for Reno racing, you would want to check the rules 1st. Super Sport does not require that 5 kits be produced and sold to make your plane eligible to race, but as of the 09 season, this was the case for Sport class racing. So, you would be restricted to Super Sport, unless your plan is also to produce your plane as a kit.

I do not know what equipment you are flying now, but if you need to beg borrow or steal something that could be used to attend the PRS this June, I would recommend you do that to get a feel for what Reno racing requires in terms of skill and equipment.

Cooling lines/aft radiator: run 'em in a sealed tunnel to protect the pilot, or build a secondary containment duct; reduce that calculated risk as much as you can.

Kevin Eldredge is building his next NXT with V8 power (Trace Engines), so your idea is not that far out. If he pulls it off, he is gonna be very hard to catch!

Your drawing looks great -- good luck!
Mark
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