HighPlains

My Feedback: (1)

ran a bladder on an old voodoo, long time ago. Doesn't it go rich just as is runs out of fuel? If you got 4 oz of fuel, with 15% it will run about 2 minutes. If you run 65%, maybe 1 1/2 tops. I ran K&B 6.5's for a few years, I might still have a few parts left over, but not too much. I've got a real nice one left with the rod sticking out of the side of the case when it broke. They seemed to do best when set at around 21,000 to 21,500 range, but that was with the 4" (or 3 1/2") open mini-pipe. Your running a full pipe? Setting the rear rotor is important to getting a steady needle setting. You can remove the rotor, and lap the back plate on some 600 paper on plate glass with some oil. Then the rotor is around .004 to .006 (can't remember too well, but in that general range). Use two feeler gauges to set rotor.

combatpigg

My Feedback: (3)

Yes, if everything is working perfectly, the engine goes rich right at the end. I will run this thing as hard as GOD allows, and if / when it pukes, then I will reload with different ammo. The good news is that the bolt pattern is the same as some contemporary engines that hold up better to high RPMs. I might get lucky and find the weak link before this thing gets trashed, if I need to make a better rod, then that's what I will do. Thanks for giving me redline recommendations, if I can prop this thing for optimum performance and it fails, at least I know it died a predictable death.

combatpigg

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Still inching forward. I found time to make a bladder tubing adapter to mate the fuel line to the latex bladder tubing. To some of you, this might be something new to look at. There won't be any need for a seperate fuel cell, I'll just fiberglass a bulkhead in the fuselage to keep fuel out incase of a bladder explosion.

combatpigg

My Feedback: (3)

All is not well in the progress department, the engine cowl did not have enough head room, so I had to raise the roof 1/2", and am in the process of refinishing that plug. I also decide to cast the next lower half mold as a single piece, instead of having a joined pipe tunnel. This way there will be less exposed seam to hide on the fuselage, but it will mean that I will have to make a floor for the pipe tunnel and apply it after the lower mold half is finished, at least this seam will be inside the fuselage. This revised fuselage will probably be lighter also, because I think I made the first pipe tunnel too strong. I am in the process of making the stab/elevator. I went with the recommended area of 12-15%, the first stab I made is roughly 10"x4.75", with the corners cut off the net earea is 14%. This looked kind of tiny, so I made a bigger one for comparison that came out to 19% and looked at it. It might look right on a 25 sized sport plane, but the 19% stab DOES NOT look right, when compared to the planes that DS showed in the other thread. I am showing [for those who have never done it] my method of marking contour lines on the balsa block. These are the guide lines for sanding if you want to make an airfoiled stab. If you have a good assortment of sanding blocks dedicated to balsa work, they last almost forever, and will make short work of your shaping jobs.

der_steuermann

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Hi CP,

according to the last pic the stab is located too near to the wing. You may want to move it about 2.5� backwards. The longer the moment arm of the lateral axis the better since we don’t want to build a pylon plane...

As for a structurally strong enough stab a sandwich construction is mandatory (please view post #33).

Nice work so far!

combatpigg

My Feedback: (3)

HI DS, I KNEW you were going to tell me to move the stab back! Even as I was placing the notch in the mold, I was telling myself that DER STEUERMANN is probably going to have me move it back! Consider it done. You obviously have an eye for what looks right. The corrected plug is waiting for the mold release to dry, then I will make a new mold tonight. My styrofoam curing oven gets up to 112 degrees with only [2] 60 watt bulbs, in a 35 degree workshop. I am almost done with the stab. I am using 2 layers of 2 oz cloth, and a top layer of 3/4 oz cloth on both sides. The elevator joiner I made with 1/8" music wire, 1/8" square brass tubing bearings, and a 4-40 threaded rod stub that wraps around the joiner wire. I silver soldered it. The hinges are done with plastic EZ hinges, laid across side by side across the entire length of each elevator half, it seems to be just stiff enough..

der_steuermann

My Feedback: (2)

Please do not silver solder the elevator linkage or any other linkage. Solder is too soft for that application and is prone to fail due to the high-frequency engine vibs usually observable. Also a single flutter can cause a collaps. A nice welding will resist all stressing much better here - how do I know

Generally - it is highly advisable to establish a short lever at the servos and a longer lever at the control horn to minimize linkage clearance.

combatpigg

My Feedback: (3)

HI DS,This isn't low temp[800 degree] tin/ siver solder, it is a high strength solder that has to be applied to red hot metal. Are we talking about the same process? I think this is more accurately called silver brazing. I have not had any luck with attempts to weld music wire in the past. With silver brazing I believe you could make a sheet metal tuned pipe, and it would last.
If you have had a failure with using this method, thanks for stopping me! I think I would rather go with brass brazing instead of welding if I have to do this over.

Rudeboy

I think it will hold... providing you were able to keep the gaps small... the smaller the better.

Copper brazing is VERY strong also. At my former job I regularly had to test copper brazed pieces (quality control)... it was VERY strong when properly done...

combatpigg

My Feedback: (3)

Yes, I think DS is talking about the low temp solder being no good. I have yet to fail a silver soldered[ brazed] elevator joiner done like this, so I would like to get some more verification before I junk this part. The finished stab weighs 2 ozs. I think I will make another one any way while I have the stuff out, maybe this time with less glass to see what the strength difference is. This one is strong enough to shovel dirt.

der_steuermann

My Feedback: (2)

Well, in the meantime I only trust 'true' welding when talking about these linkages. I call on a local buddy equipped for for that kind of job...



P.S. Same applies to custom exhaust headers.

combatpigg

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Well it has been awhile since there was any good news to report. The bad news, this plane was going to end up weighing about 4 pounds. I decided to remake the pipe tunnel/ cowl and to build a lighter stab and wing. The stab is made from 3/16" medium balsa with just a single layer of 2 oz cloth glued to each side with medium CA. The end result, this stab weighs 1.4 ozs, the epoxy resin /glass stab weighs 2.2 ozs. Not much help, but a .8 oz less in the rear of this long fuselage equals 3 or 4 ozs less weight up front needed to balance it out. The pipe tunnel is 2 layers of 2 oz cloth and it weighs 4.4 ozs. The first one was 4 layers in some spots and it weighs 9.8 ozs. So far I have eliminated 6.2 ozs. The original wings both weigh 14 ozs. The new one is white foam with 1/16" balsa sheeting. I stuck a 3/8"x22" kite tube in the center section. I glassed it with a single layer of 3/4oz and 2 oz cloth on each side. I anticipate this wing will weigh just over 10 ozs when it comes out of the oven. The total [projected] weight of this plane is 3.25 pounds which sounds much better !

thisoneused

My Feedback: (-1)

Well...I'll probably be the bad apple here, but what the heck!!!
I personaly prefer to buy the all composite Miss Candace produced by "H&M Racing" for my speedsters. These airframes are competition pylon winners. Equiped with a .40 they can reach your 200mph mark your looking for.
Maybee you're just wanting to scratch build your own with the intent for personal gratitude and satisfaction that you can only get by doing so...??? If this is the case then I will say nothing more than good luck in your quest for speed! [8D]

Jim

der_steuermann

My Feedback: (2)

Hi,

I am convinced the observing reader has recognized that the author of this thread - combatpigg - is pushing the envelope significantly here. Obviously he’s like many of us. He likes to go an individual, possibly innovative path to reach his personal goal!

So I believe the speed freaks rather would expect criticism (sorry for the hard term) from the more technical or design-wise point of view. Subsequently the reader - while reflecting previously unknown facts - would be effectively supported improving aerodynamics and building techniques of his/her future speed plane project.

In fact it would be hard to further reduce parasitic drag on CP’s speed plane design - unlike Q-40 or F3D plane designs which unfortunately are limited by certain rules.

So we should hesitate to compare a pylon racing plane with an “absolute minimum drag� speed plane since they represent two very different approaches (particularly fuse cross-section, prop selection, airfoil selection, layout of the moment arms, flight style, weight).

We should keep in mind: CP’s 200 mph speed target is VERY conservative and will easily be reached with the ole 70ties engine technology that K&B .40 represents. Just imagine his plane’s potential if powered by the MB.40 engine turning about 10K faster in flight unloaded... For comparison, it is possible to fly over 200 mph with much smaller engines using this type of “zero drag� airframes.

Yes of course everybody has his personal preferences and approaches. But I’d like to add that from personal experience the scratch built ‘strategy’ is the only way to gain MOST speed – which indeed is a worthwhile goal while contributing to the Extreme Speed Prop Planes – forum.

The scratch building procedure allows us speed addicts to incorporate all the nice little tricks which altogether will add substantial top speed – that is the key factor. Beyond that you will own an individual speed plane which will be really hard to beat – even when equipped with a vintage engine.

Mike Connor

My Feedback: (5)

Well put der_steuermann. I have had people come to me for advice on speed but you and others in this forum make me the student. This thread is great and I follow it with interest.

combatpigg

My Feedback: (3)

HI D.S., You should hear me get my thoughts out in the open about the "GREAT ARF EXPERIENCE" over in the ARF forum! It would never occur to me that buying someone elses' creation is an option here. As far as I know we only live once, and doing things for myself maximizes my lifes' experience. I built my own house, built my own 1/4 mile drag racer, and I build my own planes. This plane continues to make small progress, I finished the painstaking chore of gluing the wing in. The servos are in also. I mounted them to spruce rails that are glassed to the fuselage sides. I made a pushrod for the elevator with 4-40 threaded wire ends that are epoxied into carbon kite tubing with a 1/8" inside diameter. I scored the wire to give the epoxy some bite. I am in a holding pattern until MACs makes my header. They did not have one in stock since it is an out of production engine. I will make one concession to the guy who would rather fly an ARF pylon plane, I bet it is better looking than this one is going to be! I wont lie to anyone here, I think this is the UGLIEST plane I've ever built! But it will be a thing of beauty in the sky if all goes well. At least I am happy with the looks of the "pan" side of the fuselage. The cowl side could be restyled somewhat, but this shape seemed like the simplest way to move air around the front end.

daven

My Feedback: (1)

I enjoy flying my "arf" pylon planes, but I am really enjoying this thread and the work C.P. has been doing. Building molds, and pulling parts is an art that takes a lot of skill and practice. Looks like your on track, although a little on the heavy side. The weight will effect your take offs and landings, but for straight line speed, it will have little effect and will most likely fly more stable in wind due to it.

combatpigg

My Feedback: (3)

HI DAVE, Yep, this thing is heavier than the state of the art F1 that I picked up and held the other day. Most of the fuselage was about as firm as a shampoo bottle! The wing hold down area and firewall was in there just good enough to do the job. After putting that model down, I went straight home and re made the wing,stab and cowl/pipe tunnel. The pylon racer fuselage gets alot of it's strength through its' shape because there are built in creases, changing contours and character lines. It would be interesting to see what the side by side speed difference is in a drag race between the racer and the speed ship with identical engines? Gotta go now and start looking at guided missile paint scemes[8D].

thisoneused

My Feedback: (-1)

I hope no one became offended by my suggestions of purchasing a composite aircraft to achieve high speeds.
I started thinking of the idea in wich someone might be out for his own satisfaction of designing the aircraft from start to finish and accomplishing such high speeds. It truly is amazing when an individual can start from concept to finished product using nothing that has already been figured out for you and still achieve the performance of todays computer designed, all composite high speed racers. I only thought of the Miss Candace because of the engine choice being discussed ".40" and its already proven potential for high speed performance.
Further more, I too have scratch built many planes and enjoyed the thoughts and comments from others making comments like "you made that from what?" or "I cant believe that thing wasn't a kit!" It truly is a good feeling!
Good luck to you and I hope to see some in flight pics or better yet video!

Have a nice day,
Jim

combatpigg

My Feedback: (3)

Hi JIM, Well if it was not for DER STEUERMANNS' advice as well as tips from a few others, this thing might look like something that HOMER SIMPSON designed! The mental gymnastics that you have to go through with a scratch built plane is my idea of a good time. You know, you start out with a white sheet of paper and an empty spot on the work bench, and a few trillion neuron firings later out pops a plane[X(]! I could have built this thing 6 times already out of wood, but it would have been difficult to achieve the same compactness. I still might try a woody speed plane, with just a FG cowl someday. I have a LANIER ARF PREDATOR,[it is a piece of crap that came with several structural and cosmetic problems that took my time to correct]. When I fly it, I feel nothing, it is just a tool to race with. It is fun to race and it is also fun to sport fly it, but there is something lacking about the whole experience.

combatpigg

My Feedback: (3)

Some photos of progress. It took 3 PABST BLUE RIBBONS[sm=bananahead.gif] to get the control linkage to this point. The bladder just barely fits[perfectly] and I did a drip test to guesstimate where the best spot would be to solder on the linkage arm for the mixture control/ fuel shutoff control. The next step is to glue on the pipe tunnel.

Razor-RCU

My Feedback: (50)

Rock on CP! Keep us posted ---

I love following along with this speed project...

bob27s

My Feedback: (19)

That looks quick just sitting there

daven

My Feedback: (1)

Looks good. How do you think you will come out C.G. wise?

Looks like a long nose, even with most of your gear behind the wing, you may struggle with the C.G.

thisoneused

My Feedback: (-1)

Just wondering...are you worried about this area being week at all?