Zman39

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Last weekend, I got my little speed plane, the Meerkat to 182mph. I made a few changes during week such as fiberglassig inside of fuse toward front, putting a little better racing wheel on that were more streamlined, doing some extra balancing on prop and most importantly, rearranging things so I could fit my gps inside fuse instead of right behind engine head which I am sure was causing some drag. I am happy to report, it outdid itself by 12 mph!!! Official club prop speed record of 194mph!! Happy camper seeing the thing was thrown together with stuff I already had laying around. The airfoil which was renamed bs airfoil after last week I believe is playing a big part as well as the planes small size and of course the SJ 50. Anyway here are a couple pics of plane and GPS. Enjoy!

Kmot

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Congratulations! That's hauling the mail allright! [sm=thumbup.gif]

Mike Connor

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Did your camera man show up?

larrys4227

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A bunch of us did, but no video .... the plane was too fast anyway. LOL!

Way to go ZMan .... damn, the Meerkat was crankin today! Woohoo!

See ya at the field, Larry (Larrys4227)

Mike Connor

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A video would have been nice but the audio is what I was looking for. With this kind of speed claim I suspect many will want some type of verification.

soarrich

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With the firewall hanging out still. 6 mph until the Hall of Fame, make a cowl for that think!

200 MPH is in reach!

freakingfast

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Loose the landing gear, make a cowl and me thinks 200mph.

ecoliburger

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What prop size are you running?

soarrich

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CrashPro

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Very impressive.....who sells that plane?....

Zman39

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Thanks guys for the positive comments!. It has been a lot of fun and a lot of fuel burning to finally get this little screamer moving, To answer a few of questions, I am attaching pic that shows how tight I am on room to get anything looking like a cowl on this little monster. basically the engine is the cowl...lol. The plane is totally scratch built with a fully sheeting foam wing. It has WHAT I call a laminar airfoil which I believe is playing a key role in its speed capabilities. A good article on laminar and its drag reducing capabilities can be read here: http://www.aviation-history.com/theory/lam-flow.htm. I am running a Sport Jett.50 with an ultrathrust racing version tuned muffler. The plane weighs just 2.8 pounds dry RTF. I have to stay in the 8" props to make the pipe sing for whatever reasons. Dont get me wrong the plane is fast with a 9x7 and is on the pipe but hard to explain but there is almost a second stage "on the pipe" when going down to 8" prop (maybe due to lighter weight?). The only bad part about this is I am guessing the engine is unloading around 25K which is probably a bit much for the SJ50 but it is not overheating either. But it is distorting plugs regularly at these speed runs. I will most likely prop it up some to get back in recommended rpm band and just have fun with plane at a reduced but still fast speed. Loosing landing gear may get me a few more mph's, not sure how much but would also require me to reposition the engine to keep pipe from being landing gear...lol. Due to small nature of plane that would put carb way above tank and not sure how the Jett would like that?

My intentions were to never break any records or whatever, just to put something together with stuff I had which included the SJ50 laying around. It has been a fun and time frustrating project but certainly worth the effort.

Thanks again for comments.


Z

cncswiss1

that can be cowled,pain in the tail, but you are sooo close. and mufflers make great gear...
you flying off grass or tarmac?
there is an anti abrasion chafe tape used in sailing crowd for leading lines across stuff, great for belly / muffler landers
for example http://www.layline.com/product/11668/s
or http://www.apsltd.com/Tree/d93000/e91530.asp

Zman39

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I can land on either, grass or tarmac. May look into that stuff.

Until this thread I had no idea on what 200mph means as far as AMA goes. Is there a link somewhere I can read on it? I wouldn't have thought it was a huge deal seeing that there are some composite type arf speed planes out there that when electricalized properly have been recording 220 plus. But last time I priced the setup it was well over 1k with the juice batteries. That is what got me working on this project .

Zman39

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I looked at those links, no mention if they can take the heat of muffler. Any ideas?. I also was browsing and saw some people that believe in polishing the covering with liquid rain X, not sure if that would help.

MJD

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Are you running standard APC props or pylon props?

Zman39

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Best speed actually came off an apc sport prop, but have been trying a huge variety, all apc's.

Ed Smith

A note of caution.

APC has recommended max RPM limits for APC propellers. For the APC 8.8dia series of racing props the RPM limit is calculated by 225000/Prop Dia. The 25k rpm quoted is dangerously close to the limit. One would hate to hear in the next report of a blade stuck in somebodys ear.

Ed S

daven

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Any wax would work, and yes, many of the pylon guys wax/polish their planes.

Not sure about Rain-X, I'd test it first.

I use Race Glaze (polish) works well and does not build up like wax can.

I've been saying all along that you can go 200 mph with a balsa/foam (under $100) worth of materials.

Good job.

Zman39

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Thanks Daven for the tip and remarks,

Where would be a good place to find this race glaze, might give it a try

'
Z

daven

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this is what the bottle looks like, you can buy it online, but with shipping it gets kinda expensive. I'd take a look at some of your local auto parts stores (checker, autozone, pep-boys, etc..) I don't think everyone carries it, I normally buy it at Fleet Farm, last time I think it was like $11.

http://www.afterthoughtsauto.com/racglazpolse.html

daven

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I'd be curious if you tested its effectiveness. GPS the plane unwaxed, then was it at the field and try again.

I like it for racing because it keeps the goop off the plane (including bug guts), and most importantly, allows the easy removal of the lane identifying stickers used in pylon. I've never thought it made a noticeable difference in speed, but never tried and objective testing.

bob27s

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Great post Z....

Get that video/audio next time out... we can find out the in-flight rpm and the velocity .... to some level of verification

The engine is fine at that rpm.

We use to run the SS40 engines with the 8.5x7 and 8.5x7.25 props - turned 20K on the line, and unloaded like you have been seeing, but it was more like to 21,500 or so. The SS type (LX type) muffler found a harmonic that it loved up in that range - was popular for SEMPRA and CAPS racing for quite a while.

No doubt your SJ-50 is hitting a similar harmonic.

As Ed noted, be sure to stick with the D-1 props. Those are the only props really designed for that sort of rpm.

Of note to those viewing... what Z has built here is not much different than the clipped-wing Q-500 design Ive noted to a few for speed use. Simple, easy to fly, inexpensive, and for most, pleanty fast.

Bob

Zman39

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Thanks Bob and others for the help and advice. I will give these ideas a try. Just wished I didnt have to wait another whole work week. .. Bob sent you pm.


Z

bob27s

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I got the pm.... thanks..

try going just a little bit richer on the mixture for launch. That will help on the plugs. If the engine is unloading like that in the air, it is going to need much more fuel than it does on the ground. Backing down until it almost falls off of the "pipe" is where you want to go.

Zman39

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Thanks again,

I will be switching over to D1 props at these rpms. Anyone know of an article out there on how to clip props properly? Never done it but may have to to get one of these pylon props into the rpm band it needs to be.

Thanks

Z