davidej

I thought that PROPTOPs suggestion (which is based on WW2 thinking) has been superceeded by the 'area rule'. This rule suggests that fuse area should be least in the wing region, as the wing can be considered as part of the fuse cross-sectional area.

It certainly applies to military jets (look for example at a Phantom). Is it only for supersonic planes or does it apply to all speed types?

Very best of luck. sounds to be a great Project.

davidej

proptop

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Hi David...I was mainly commenting on the theory or idea that the widest point shouldn't be at the firewall.
The area rule might actually be better, but at the speeds our airplanes fly, I personally don't think there will be a noticable change in speed. Could be wrong of course...
Maybe, if the waist, or X-sectional area was at it's smallest right where the high or thickest point of the airfoil? I believe the F-102 was made that way, after the disappointing speed of the early version.

I think the area rule makes it's difference when you get to the point where compressability starts? Or shock waves begin to form? I don't really know, I'm just speculating here, maybe some of the other guys with some real knowlege on the topic will?

paulgibeault

Hello Chuck,

I tried to post a detailed letter here but it got lost, much to my chagrin!! Here's my second try....
WRT disk rotor clearance: The correct clearance is .003" set by using two .003" feeler guages on each side of the disk rotor.
That way it won't tilt of course. I don't know if .005" is really that bad though....

My experience shows that shorter mini-pipes favour higher rpm & longer mini-pipes favour lower rpm. The most boost a mini-pipe
will give you on the ground is 1000 rpm. My standard ( minipipe only) length is 3.375"

Along with the right head clearance is the right head FIT. The ideal head should fit fairly snugly into the liner. If it's at all loose,
the engine can lose up to 1500 rpm. A correct Nelson plug head can add 500 rpm, incorrect & it's slower than stock....
K&B's respond really well to mixing & matching to get the best fitting parts assembled into one engine.

I myself still compete sucessfully with the old K&B 6.5, & think it's an excellent training engine that allows you to grind away to your hearts content & if you happen to screw up, you're not out much. K&B's are plentiful, you just have to do a bit of research to find them. Why right now, there are 3 or 4 new Clarence Lee tuned engines on ebay from that late Ed Keck's estate.

Personally, I have quite a number of engines & spares if you're interested. BUT K&B made a number of different versions of the SR2 & SR3, so I have to either have the engine or know some measurements, as there are 2 lengths of con rod, 2 dia's of sleeve's,
2 different wrist pin hts. on the piston, several different head types,etc.....
email me at: [email protected] if you're stuck for engines/parts, & I will try to help you.

You would be wise to keep the ground RPM's to 20-21,500, as the K&B will unload quite a bit in the air. So, use the engines torque to turn a heavy pitch rather than go the high RPM route. ( HI rpm works too...but the engine doesn't live very long in the 26,000+
range where I've been) Although for short 30 sec tank runs, 70% nitro works in C/L, for r/c work & longer tank runs, there is no point in going past 50% nitro. ( this is what the engine was originally designed to run on)

I really like reading about your project & wish you the best of luck on it.

Cheers,

Paul Gibeault

mrmoki

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You bring back memories of when I did this. Lets not say how long ago, lol. Mine was a little larger, with a cheap engine, and still did over 100 mph. Remember the most important thing,,, CG... have fun...

combatpigg

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HI PAUL, thanks for your offer! I had a feeling that this engine was still getting used in C/L SPEED. I have put the plane on the back burner until my son gets home on leave in JUNE. I still need to come up with some head shims, might have to go the "coke can" route. The other detail to take care of is to balance the engine to compensate for the piston and rod lightening. Thanks for taking the time to give me some set up info also.

Rudeboy

I don't know what american coke cans are made from, but over here they're steel... it's great stuff, I use it quite a bit on planes... but not for head shims.

combatpigg

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American drink cans were made from steel many years ago, but they are made from aluminum with a plastic liner nowadays. They cut easily with cuticle scissors.

No1pylon

Have you ever tried a carbon fiber and balsa main spar this is light and extremly strong when done correctly
you should epoxy glass the whole spare in.
This is how it is done in pylon the balsa is vertically grained

combatpigg

My Feedback: (3)

Yes, I encased balsa spars and leading edge with carbon strand once for a 3D model. Alot of trouble, but the end result was very stiff and light. How about just routing 1/8" wide grooves in the foam wing and bury saturated carbon strands in a few key spots? The problem of how to make the wing torsionally stiff still seems to boil down to having light glass cloth over balsa sheeting.

Rudeboy

I have been using a balsa - CF - balsa sandwich for many years on my funfly planes... The CF laminated spars together with good webbing between the spars make for a very strong wing.

For real strenghth you need something to keep your carbon strands apart. The carbon won't fail under load, but the foam will... hence the webbing between the ribs on my funfly planes.

Torsional stiffness... a layer a glass at a 45 degree bias always does wonders... don't leave it out

combatpigg

My Feedback: (3)

My SON will be home in about 4 weeks, then we will see what this plane can do. I think the next one will be smaller and designed less around the fully enclosed pipe. After seeing the real life outcome of this plane, as I hold it in my hands, I can see things that I would like to do different, that I couldn't see when it was just a drawing. I wonder what DER STEUERMANN is up to? I think he got bored with this forum and wanted to rename it the," Well I kinda want to go fast if I don't have to work at it or learn how to do any thing new, forum" When is the EUROPEAN SPEED CUP due to get started this year?

xanaphyst

My Feedback: (17)

hope those 4 weeks go quick.....I can't wait for the flight report !!!!

xanaphyst

combatpigg

My Feedback: (3)

Same here! How have you been? Hopefully you put in enough time at work to slack off and enjoy the summer time. Have you checked out the CHILL FACTOR X yet? It's in the, " NEW SPEED PLANE " thread.[X(] BAD A**!

crasharama

Hi Combatpigg,
You keep saying how ugly it is throughout this thread, but I think it is very cool, even a bit of a retro feel. If it was around way back in the 20/30's full scale & floats, you could have won the schneider trophy !!!!

I think this has been a credit to both yourself for building it, & the techo knowledge world wide to get it to where it is now. Just show's the level of expertise that is out there burning little holes in the sky all over the world. Imagine if all this combined thinking could be put toghether in a full scale version...............

Hotrodkid

i agree that its a sexy looking plane , but i also see how it could be refered to as "ugly"

when u have a picture in ur head of what u want, and the plane winds up having to look totaly diff in the end, it can look ugly in ur own sort of way

alot of cars on the road look horribly ugly compared to the concept car they were born from ... doesnt make the finished product any less of a beauty tho

Evil Homer

Hey CP, I think you have done a brilliant job here, again hope those four weeks go real quick!!!

combatpigg

My Feedback: (3)

Thanks for the words of encouragement! That single, inboard aileron is the main thing that has me wondering. Hopefully it will have enough roll control to at least counteract left roll on launch and keep the wings level on dead stick final.

xanaphyst

My Feedback: (17)

I've been doing great...Looks like work has slowed a little so I'm getting the mini dust back under way...I'm going check out the chill factor x right now !!
Great looking speed plane you have there !!!!!!!!!!

xanaphyst

DHG

My Feedback: (7)

The one-aileron thing reminds me of what my drivers' ed instructor used to say: "Over 70 mph, you're not driving the car. You're aiming it."

Duane Gall
RCPRO

No1pylon

single aileron works well if you go fast enough it is very effective you wont notice the difference of missing an aileron just think less drag more speed

RHarding

My Feedback: (3)

I flew Q-500 back in the 70's. Would like to build one like we flew back then. Nothing fancy. Just a straight forward Q-500. Anyone out there have a set of plans that I could get a copy of?

Richard

magnumeng

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Has the maden flight been taken yet?

combatpigg

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Not yet. My son got here last week, and all we've been doing is flying combat. The speed plane will come out of mothballs today, and I am going to work on the engines' balance and glow plug destroying issues. The plane sure does feel heavy, I will be amazed if it flies. If not, I'll do a lighter lay up and start over from scratch. The next plane will have the benefit of lessons learned on this one, this was my first ever attempt at as much fiberglass on a plane.

magnumeng

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Any flight report yet?

combatpigg

My Feedback: (3)

I got the plane all ready to go in JUNE while my son was here, and the engine started spewing tons of black gunk, and wouldn't rev up for us. I haven't even torn into it yet. We were too busy flying RC combat, working on the house and getting ready for another big job to start up at work to give it any attention. Thanks for the interest though. At least I can do a post mortem on the engine, and then decide on the next move. RC combat sure has a way of moving the other stuff to one side, I do like to bring a speed plane along for a little variety. So far, this year I've logged about 25 hours of actual combat air time, and who knows how much time behind the scenes to support the air time?