Pond Skipper

I have two Sportsman .15's and a Olympic .15 the one in the pic comes in at 143g about 5oz. / in retrospect my Magnum .15 comes in at 7.34oz with prop.

This is a light compact engine on 25% nitro will spin a Cox 6 x 6 at 13,700 - 14k rpm / 80 mph not bad!

MJD

My Feedback: (1)

My goodness, never heard of Cox 6x6 props. Them's ol-l-l-d packages! I wonder how fast an .074 would spin the same out of curiosity.

Pond Skipper

I have 4 of these very rare 6x6 light weight props specially made for the Sportsman Engine and the Cox Comanche CL plane which comes up for grabs on Ebay once in a blue moon most don't want to give up that plane it is only .15 plane they made if I recall. There is a Youtube vid on it.

Here is my other Sportsman with a throttle sleeve can swing 14,170 rpm 81 mph unloaded my guess 15.8k / 90 mph

132 G / 4.6 oz lightest version with the sleeve.

Pond Skipper

The prop would not hold up to a TD .15 think it would flex too much loose pitch.

But a AP .09 or a Norvel .074 and TD .09 for sure I plan to try one out on this plane thread.
I think the nature of the hot TD .09 will edge up to 15.5 to 16.6k ish rpm unloaded. 95 mph.
I just check Ebay they had one up for grabs so I now own 5 of these props that should do lol.

Pond Skipper

For fun I matched up my Saito 72 to the Lil Miss as a 1/4 scale plane just big enough to enter a big bird fly in with it.

Pond Skipper

Olympic .15 / 135g with a 6.5 x 6.5 German speed prop if with 30% nitro at 16.2k 100mph
Spins a 8 x 4 /15.42k rpm static.

Mr Cox

That's amazing, 6 pages of text and 100mph, and not a single piece of balsa has been cut

Pond Skipper

Neat huh..no photo's shown of a single spec of wood dust even



I have transfered the formers on the plans over to poster board for templates and cut out the lite ply formers on Sunday.
Will post some pics once the stringers are glue on to show the frame perhaps tonight after work.

Condor84

Hey, it's Condor84 from over at RcGroups. The more I study the preliminary plans, the more I am beginning to love the design. However, I was wondering; do you think that with a few more stringers added and some select formers replaced with balsa, whether the fuse could be sheeted with balsa to help shave some weight if I were to go all electric? I believe it could, but I thought it may be prudent to consult the designer!

I just got a new scroll saw, and started building an aileron version of Al Wolsky's 48" EAA Headwind as a .10 size electric, but after I break in the new saw with that one, I would very much like to build your design. It just hits that nostalgic looking aircraft button for me.

Also, I can't believe I've been using a band saw, jewelers hand saw, and xacto all these years! I don't think I shall ever go back either.

Pond Skipper

Hey Condor thank you and congrats on the new scroll saw !!! Yes you could go light weight the conventional way with more stringers and formers to control the shape and add strength to the design. The ply egg shell method does not require all that extra effort. The ply shell be will doing the majority of the work leaving only the bones to form the shape and provide attachment points for RC components and the power system. This particular size plane should do well as a balsa build should you deside to build one from120w + motor to 300w if done in ply. I hope you enjoy building your Headwind project and it gives you many hours of air time.

perttime

Agreed: a couple of stringers might be good for a balsa build - and/or you could cover the balsa shell with paper, pantyhose, glass, or something.

Pond Skipper

Yes at least two more stringers per side to avoid cracking the balsa skin when handling.

Pond Skipper

Today I went to the M&M Metals and handed over the landing gear design. I was quoted 15 bucks for them to do out of T6 aluminum lol easy enough!

Should get it Friday is the word here is the design will hold it down with nylon bolts.

Pond Skipper

My parts came in for the AP .09 Hornet a optional engine that may find a home on the Lil Miss if nose weight is a plus.
I didn't like the exhaust restriction with the stock muffler the exhaust tube is rather small in dia. Other's have tested with and without
and without question lol less was more. So still want goo control but rather have the more rpm.

I used a 50- 60 size saito muffler and steel threaded coupler the bore is larger the walls are thinner since the coupler is made out of steel and thus the engine breath more.
Pics plus product stock numbers for anyone wanting more rpm over the stock muffler.

Saito Engines Muffler Manifold (Cast):FA50-56, SAI5075B $13
Saito Engines Muffler,10mm: D-F,II,JJ, SAI5074B - $17
10 x 1mm thread

combatpigg

My Feedback: (3)

It's surprising to see how tiny the stock exhaust port is.
It's also surprising to see such a dramatic improvement with the steel fitting. In larger sized fittings there doesn't need to be as much of a size difference [if any].

Pond Skipper

Yea the lackluster effort on the stock muffler has robbed too much power for my taste so worth throwing a few dollars at it.
The Saito muffler has a baffle cone with 6 large vent holes, not a simple straight tube you can't see out the other end.
It breathes very well but has back pressure I look forward to using at some point.


On another note after a few weeks two more of those lovely 1.25in aluminum spinners came in woot!

Additions shown on the Norvel .074 and Olympic.15 although the MK II .15 will end up with the spinner.

aspeed

I have shown these pics before, but I drilled the hole inside the thread bigger, and drilled out the exit stinger for a 5/16" - 32 thread, and made the hole 6mm like on the F2D planes. They used to be 8mm. It was about 4 mm on the stock AP. It really affects the .15 motor a lot. I also made a control line carb and spray bar/needle valve for the .15. It is around .220" quite a bit bigger than stock. It will not run on suction.

combatpigg

My Feedback: (3)

That's nice work Aspeed..!

PS...a spinner even for your "Product Engine"...?
I guess you didn't want the little guy to feel left out...?

Pond Skipper

I understand cox product engines as mass produced reed types for CL plastic planes.

TD and Olympic engines had been produced for performance applications of their day.

Yea the spinner will work with the TD .09 on the lil miss and is shown in the final set of printed preliminary plans.
I have sourced some soft aluminum for the cowling

on the AP stock muffler here are the differences
6mm ID and exhaust tube 3.9mm ID
Saito 60 size muffler 7mm ID with the steel adapter and 6.5mm ID exhaust tube

Pond Skipper

Alan did you ever use the adapter for a pipe?

I see the 15 uses the same size muffler ouuuuchie

aspeed

I put a pipe on when testing the .15 with a 7-5 MA prop, and it didn't change the rpm at all. It would have to be adjusted for length or prop dia. The Ucktam pipe is not adjustable, so it would need to be flight tested. At least the pipe did not slow it down like a muffler. I think the Russian F2D props would work well on the .09, they are too light for the .15 using the stock rod. I started a delta for the .09 and bought a mouse can to maybe try out. I gave the adapter away with a head that I made up for a guy, and it is too cold to do any machining for a couple of months now. I did buy the metric die though.

Mr Cox

The Utckam pipe doesn't do anything below 20000rpm, in my experience. You could try a smaller prop, like the APC 6.5x5 instead, that worked on my MVVS .15.

But I guess the exhaust timing is another issue, you cannot get much power boost on the stock timing. I think a header and after-muffler works just as well then, or even better as you have wider power band.

Pond Skipper

I recieved the phone call today to pick up my aluminum landing gear blank so out of curiosity I used some folder stock to see how the dimensions look once bent.
I didn't want the folks at the metal shop to put the bends in till I have confirmed what will work.

Pond Skipper

Using the tape method to protect the now polished metal I have protected the lil wonder from getting scratches while bending the angles in.
I made two angle templates to check my work as I bent the metal in a vise. The pattern gets me 9" spread and 10 1/4" at the wheels foot print.

Pond Skipper

By Raptars Hammer she is done


2.6oz of beefinheimer, tapped and threaded for wheel axle allen head bolts into the legs leaving only 1 washer and nut to retain the wheel. To keep the threads from munching on the ABS wheel hubs I coated the threads with CA. To hold down the landing gear I tapped in three 8/32nd (4mm) threaded holes for nylon break away bolts equal to a sum total of 1/2" worth of nylon.
If that tends to break away to easy I could go with two 1/4 nylon bolts up front and one 8/32nd in the back or three 10-24th bolts (5mm).