More power always better?

[Stevey]

Re: More power always better?

Ok well having seen what everyone has said I think I might aim to build an engine with a peak power curve between 3500-4500rpm. I also think I may begin building a garage/hanger to start building in. It wont be anything special just something to keep me from the elements and something that will hold some heat in and potential thieves out. I have built up a credit at the local lumber yard so I can do it for free basically.

Then I think I may start construction on some molds for the fuselage. I want to try and get a fuselage finsished on my own dollar then have something to show my "advisor" and something to show my possible sponsors. Then will come things like structural supports, engine mount, landing gear etc. I should be able to do most of that for half decently cheap. I will be buying raw materiels only and doing all the work myself.

Im not saying this will work. But I have made my mind up to give it a try. Like I said Im going to try and use as little money as possible until I have figured out if it is going to work. I need a new project anyways, I just got done rebuilding my camaro . I had planned on picking up an old truck to hot rod.... guess not. Anyways I have to go look over my plans, I think I have a very long journey ahead! I hope this doesnt blow up in my face.......

Steve

[number17fan]

Re: More power always better?

Steve, I didn't read what class racer you were going to build. Formula 1 , a modified Cassutt is a great place to start, Unlimited, find a F8F Bearcat that needs a rebuild, You will spend less money and be flying faster!
Free advice is always worth the price
Been there, was doing that when bad things happened!

[Apteryx]

Re: More power always better?

...find a F8F Bearcat that needs a rebuild, You will spend less money and be flying faster!

You haven't been following the prices on Bearcats lately

[Peashooter]

Re: More power always better?

A great perspective of the Bear's P-3 prop, Reno 2003.

[Stevey]

Re: More power always better?

Ok well first Ill have to let you all in on the fact that when I said 3500 hp I was just using that as a figure I dont plan on coming even close to that. I was just trying to get a handle on how props work and the efficiency of turning power into thust.

Here is the problem. I want to fly sport class. Which means I have to make and sell 5kits, I believe I can include the one Im flying though. I dont have a problem with making that many fuselages as once I have the mold its not hard to pop one off. For those of you who are wondering the fuselage and in turn the molds will be done in sections not one big fuselage. But then I have to cut all the tubing for the inner supports and stuff, which is where I would start to lose my time. I forget right now what is considered a kit by the sport class but I will check when I get home. I will finish this later Im in a bit of a rush.

Steve

[Bill Marsh]

Re: More power always better?

Steve-o

"I'll have what ever he's having" ... for courage, conviction and your personal "breakfast energy drink".

Very cool!

bm

[Skyracer]

Re: More power always better?

But then I have to cut all the tubing for the inner supports and stuff, which is where I would start to lose my time.

A friend of mine designed and built a tube and rag airplane several years ago. Before he cut a single piece of 4130, he cut and fit every tube piece using electrical conduit (EMT). Figures he saved about 1/3 the work, cost, and heartache by doing that. And, he ended up with a dandy "jungle gym" for his kids.

[Stevey]

Re: More power always better?

Bill Marsh- Sorry buddy I don’t understand, I don’t think were on the same wave length lol.

As for mocking up the frame using pipes or something similar I think that’s a great idea, maybe something along the lines of pvc pipe? That would allow me to have a finished inner structure to show possible “investors/sponsors”. It will also allow me to be able to have pipes to cut my metal from with the holes and the spots where pipes mate together already cut to use as a template. This should speed things up and make it easier. My girlfriend has said shed help me, she helped rebuild my car. She can do anything once I teach her hahahahaha.

What exactly is considered a kit? I believe when I read it on the sport class website they said it was a fuselage, motor mount and empennage. I assume that includes all inner supports as well as possibly landing gear? Oh and I know you need full instructions with the kit to detail how to assemble it. Is there any more I have to add to make a “kit” or is there anything that I don’t need that I have listed? I do not need a prop or powerplant with that kit right? I will have to recheck the sport class website {this computer wont access it}.

Last but not least, can I race an ALTERED version of my kit plane? For example if I put out a kit for lower level performance with 3 main bracing pipes going from cockpit to tail can I upgrade my racer? As in could I make it so my racing plane has 5 main support pipes to withstand the stress of racing and withstand the power? This would also allow for less weight and possibly a better handleing and comfort for the kit. I assume its ok as long as the outer dimensions stay the same as well as most of the fuselage “skin” Id be okay? I base this on the fact that I doubt guys that have full out racing glasairs etc are running a completely stock fuselage etc. Ya know? Am I wrong in assumeing that?


Thanks Steve

PS: Sorry for the long post!

[Stevey]

Re: More power always better?

By the way that prop on the second page looks sweet! That looks like it could really move some air!

steve

[wyhdah]

Re: More power always better?

Stevey trust me, it sounds more inpressive than it looks.

[W J Pearce]

Re: More power always better?

can I race an ALTERED version of my kit plane?

Absolutely. I think that Greenamyer's Legacy is further from stock than any other sport racer. The fuselage structure has been strengthened, the profile of the fuselage/wings has been changed, flaps removed (I think), engine completely different including 2 turbos with intercoolers and a different cowl to cover them. And the canopy opens opposite of stock.

Hell, Will Matthews added another engine to his sport racer, a two stoke that powered his supercharger.

Mods are safe and so far, there is nothing that defines the limits on the mods. Kit planes by there very nature are unique.

[Apteryx]

Re: More power always better?

By next year, Aerochia should have their radical NXT completed. That should be the test for allowable changes. Entirely different motor, cut down fuselage, different tail and landing gear.....

[Stevey]

Re: More power always better?

Perfect. May I ask then what is the point of having to have 5 kits put out if it can be so radically changed? I thought the point of having kits would be to make that airframe available to others, it isnt if its a complete custom. I wont be doing that radical of changes the main difference will be the inner structure. All control surfaces will be the same as well as the fuselage "skin". Just out of curiousity what is the avg hp for a sport racer? For example what would that legacy run? I read on the official NXT site that it runs 350hp. What do most use?

Thanks Steve

[Whiteside]

Re: More power always better?

Since my airplane was mentioned above.
Food for thought: What is better Mach .70 tips or .90 tips? Is less blade angle better or more angle better? What if you are running blade angle beyond 45-50 degrees?
SteadFast uses 2:1 gearing with engine 2700 RPM.
Our Propeller Diameter is 10'-2"
That equates to the low .70 Mach numbers at the tip.
Will

[440_Magnum]

Re: More power always better?

Mike, how much does "forward velocity" play into tip speed? I know I've heard many transonic tips on both float planes going pretty slowly (forward velocity)and T-6's without a "great" amount of "forward velocity"..

I'sn't tip speed independent of forward velocity?

Nope. I see the math has already been posted, but here'd the intuitive way to think about it:

When the plane is sitting still, each rotation of the prop means that the blade tip travels the circumference of a circle. Now if the plane is moving forward and the prop is turning at the same RPM, the blade tip no longer traces out a circle, it traces out a spiral in the same amount of time that it traced out a circle with the plane sitting still. Obviously, a spiral of a given diameter is longer than a circle of the same diameter. And the faster the plane is moving forward, the longer the spiral and thus the higher the tip speed.