New .020 Muffler Kit #2620 - It seems a shame to open the packaging!? - RC ideas for the .020 Pee Wee

balogh wrote:I have many antique COX engines without those flats milled and I spray some silicon oil on the cylinder thread before reassembling the cylinder in hopes that unlike castor, silicon oil will not cake between the threads and the cylinder remains removable without high torque when using a plier plus leather belt, after heating the crankcase.

Yes, quite right. I always use Winkel brand high temperature silicone grease on all threaded parts of engines. It is also compatible with plastic parts and rubber o-rings.

Daligh wrote:Balogh.

Just spotted your photo of Poinsettia and thanks for posting it. I guess you edited it in as I missed it before. You must be an uber Cox fan to go all that way!?

Yes I must admit this obsession is there..but we were on vacation in California with my wife driving down from San Francisco to San Diego and I could not miss visiting the place when driving through Orange County...I wish I could have done that 40 years ago and even go on a factory tour COX offered in their newer facilities on East Warner Ave in Santa Ana back in the 70s and 80s before they moved to Corona. (I also visited the East Warner building before driving over to Poinsettia maybe 7 miles away. )

Wouldn't it be easier to just search out the factory throttled Pee Wee? I have one of those NIB.

706jim wrote:Wouldn't it be easier to just search out the factory throttled Pee Wee? I have one of those NIB.

Hi Jim.

In some respects you are, of course, quite correct. But. Finding one may be a problem. I have been searching for 6 weeks now and seen none. If you were willing to sell yours, which you won't of course, then I believe the price would be more than I wish to pay!? I was very lucky to find my NIB Pee Wee on spchok UK and it was but 2 streets away from where my son lives. At €20 it is a bargain.

Anyways-up. As I stated above I believe exhaust throttle control is counterintuitive and I am going to attempt to use the .049 RC inlet throttle on the Pee Wee. I am looking to buy an old Pee Wee for parts to experiment with. Having said that I shall also make a split exhaust throttle just for the sake of trying it out. I like making things and have been doing so for 55 years. e.g. When my wife's VW Golf Mk4 GTI 25J (337 in USA) had an engine problem (oil pump filter blockage due to previous idiot owner using cheap oil which carburised) I made all of the special tools that I needed to strip and re-build the engine. At the same time I ported and polished the inlet and exhaust ports. The power is now over 200ps. It took me many hours but I enjoyed doing the job and the results are very satisfying.

Found these on eBay UK. I think I shall purchase the £18 one. £26+ is too much for a non-working motor!

Cox International wrote:We only declare CA$ 15 per package (10 Euros) and our postage costs are "hidden".

This has always worked very well for me here in Sweden, no extra fees and a very fast delivery, thank you very much!

Surfer_kris wrote:

Cox International wrote:We only declare CA$ 15 per package (10 Euros) and our postage costs are "hidden".

This has always worked very well for me here in Sweden, no extra fees and a very fast delivery, thank you very much!

Hi Kris.
Thanks for your confirmation. I have a wish-list ready on the COX.ca website.

Now.
Why are you messing with COX engines? If I lived in Sweden I would be spending my time with SAAB TVÅTAKTSMOTORER.

I am a massive Swedophile. I even took Swedish lessons in the 1970s. I owned quite a few SAABs. Including:1965 Sport, 1967 96 TS, 1969 96 V4, ............. I wish I had them now! I also tuned them and rallied them. When I was Technical Manager for a UK spring manufacturer we supplied SAAB and I spent many happy days at the factory in Södertälje where they built SAAB 99 Turbos.

We do get the Pee Wee RC in on a somewhat regular basis but they also sell quickly. Here is the one that sold on May 27: https://coxengines.ca/10-cox-.020-pee-wee-rc-version.html

And, good news is that we have another one that is slated to be delivered to us this week if you are looking to buy one

Cox International wrote:We do get the Pee Wee RC in on a somewhat regular basis but they also sell quickly. Here is the one that sold on May 27: https://coxengines.ca/10-cox-.020-pee-wee-rc-version.html

And, good news is that we have another one that is slated to be delivered to us this week if you are looking to buy one

Thanks Bernie but that is just about my total budget!

I am going to try to make one.

Levent Suberk wrote:

balogh wrote:I have many antique COX engines without those flats milled and I spray some silicon oil on the cylinder thread before reassembling the cylinder in hopes that unlike castor, silicon oil will not cake between the threads and the cylinder remains removable without high torque when using a plier plus leather belt, after heating the crankcase.

Yes, quite right. I always use Winkel brand high temperature silicone grease on all threaded parts of engines. It is also compatible with plastic parts and rubber o-rings.

I use these on various joints as applicable.

Copaslip for steel to steel joints and Aluminslip on any joint where aluminium is one or both components.

Considering mounting the engine in-board!
Don't know what power to weight ratio will actually fly!?
Don't know what wing loading will fly!?
The bearing housing is the rear wishbone from my son's 1979 Tamiya Sand Scorcher. It was broken years ago! I am refurbishing it for my grandson's visit in August. I shall lighten it down to the bone!
No company makes mini UJs capable of 20,000 rpm! Could use titanium or carbon fibre for the torque tube.

US Engineers managed to build the P39 (I know it was not very good so they sold it to the UK and sent if free to the USSR) so I should be able to again similar!

Daligh wrote:
Now.
Why are you messing with COX engines? If I lived in Sweden I would be spending my time with SAAB TVÅTAKTSMOTORER.

Those are way to valuable to play around with these days, they are relics that no one dares to use anymore...

As a kid we would see them quite frequently and you could easily recognise them at a distance by the sound. Sounded like a full rally race, even if someone was just going to the grocery store.

I have started to experiment with a split exhaust throttle for the Pee Wee.

The tube is a gas strut body from an old AUDI.
I don't know what they specify for the coating but it is uber hard! I tried using a carbon steel file and then emery cloth, all to no effect. I heated it to red hot and tried again. This time a diamond file actually did the job.

The groove was cut by holding the large machine hacksaw blade against the edge of the drill chuck.



I cut off the piece I needed with a junior hacksaw against the chuck face. I then finished the ends on a diamond plate using the square to check for accuracy.



It is perfectly square as there is no gap when in the digital gauge.



Then it was split along its length using using a cutting wheel in a Dremel machine. I Cut it so that one part was more than half the circumference and the smaller part is scrap. The intention is to make two pieces larger than half the circumference and then linish then until they are exactly a half tube.



Bit of a problem! The split tube above is the scrap part as I dropped the piece I needed on to the barn floor. I spent a good hour trying to find it with a powerful 450mm bar magnet (tool holder magnet). All to no avail although I did find quite a few bits and pieces I had lost over the years!

A Garnet blast in my home made blast cabinet does a great job of removing the coating.




I made 2 new halves and linished the edges. Mounted them on a 10mm drill bit with a pipe clip to keep them square and linshed them to length.


The fit is perfect for length. On purpose there is a small gap at one joint as I intend to hone the bore using a 10mm drill bit and fine carborundum paste.

Good work Daligh. I want to try this for Cox TD .010 from copper pipe.

Levent Suberk wrote:Good work Daligh. I want to try this for Cox TD .010 from copper pipe.

Hi Levent.

If you use copper it will expand more than the steel cylinder barrel. This will lead to the exhaust gases blowing past the throttle.
So. Measure the outside diameter of the .010 cylinder and I'll see if I have a piece of steel tube to do the job!

Kind regards,
Dave.

Great DIY solution, Dave, congrats. I keenly wait on the results of how it throttles...

Daligh,

I see serious problems with fuel proofing an internal engine bay in what was designed as a stick & tissue model. Might be better to install a fuel proof firewall and keep all engine oil splatter out side where cleanup is easiest. All engine exhaust has a way of finding itself inside where pressure is lowered in flight by airflow around the tapered fuselage.

Have you searched for a powered scale model design or kit of the Porter?

Generally, structure of a rubber model is not strong enough to resist the vibrations of an IC engine, or the increased weight.

I don't mean to discourage you, but see some of the problems I've run into when converting to IC engine power.

Bill

balogh wrote:Great DIY solution, Dave, congrats. I keenly wait on the results of how it throttles...

Ta So Balogh.

I don't know when I will be able to fire it up though!
I need a prop., new fuel pick pipe and spring. These, thanks to Bernie, are wending their way, with other parts, from Cox.Ca.

I also need new fuel but can't get Model Technics to reply to my e-mails regarding Irish stockists.

I do have some fuel from 1987 when I bought my 'Black Widow' for £25. I have run the single transfer port .049 with it and, believe it or not, it was OK.




Bee keeping boxes here.
https://www.coxengineforum.com/t14205-perfect-storage-for-bee-keepers

smooth_bill wrote:Daligh,

I see serious problems with fuel proofing an internal engine bay in what was designed as a stick & tissue model. Might be better to install a fuel proof firewall and keep all engine oil splatter out side where cleanup is easiest. All engine exhaust has a way of finding itself inside where pressure is lowered in flight by airflow around the tapered fuselage.

Have you searched for a powered scale model design or kit of the Porter?

Generally, structure of a rubber model is not strong enough to resist the vibrations of an IC engine, or the increased weight.

I don't mean to discourage you, but see some of the problems I've run into when converting to IC engine power.

Bill

Thanks Bill much appreciated advice.
You have more than confirmed my own worries regarding conversion from rubber to IC and regarding the overall strength and 'crash-ability'!

As to finding a powered model. There is a 40" span PC-6 available but it uses a larger capacity engine and I always wanted to RC with a Pee Wee. Back in 1976 I started to 'scratch-build' a 36" span Fiesler Storch (I am in love with STOL) for the .049. I was even intending to make the Handley Page slats function. But. What with a new job, that needed much more than a 40 hour week, and our daughter Ruth appearing, as if from nowhere, followed not too long after by Ben, I had no spare time.

Our top field is about one acre and I hope it will be big enough for a 24" span!? There is a bog below it so if things go wrong it's a soft 'splash' down!



The kit has two tailplanes. One to scale and a 115% version for flying. The flying version is split for an elevator and rudder so is intended for RC. Back in the day Guillows did supply vinyl bulkheads and IC engine mounting details but have now ceased to do so.

So. I built the scale tailplane with the following results:

#1 - My eyesight, even with my reading spectacle, is poor! I tried a 100mm illuminated magnifier but I can't seem to get everything into focus!
#2 - My arthritic fingers don't place tiny pieces very well!
#3 - My shaky hands don't help! (Probably due to lots of Evening Ale!?)
https://www.coxengineforum.com/t14200-this-evening-s-ale-night-cap-whiskies
#4 - Super 'Phatic does not penetrate very well and leaves dry joints. It does not sand down and the balsa around excess adhesive is damaged. So I bought some Zap CA to try.
#5 - The tailplane trailing edge and the elevator leading edge is too weak! I added extra strip and triangular stiffeners. I shall use wider strips there.
#6 - Thread hinges work well enough! I tried two versions. Wrap around, and needle through. The needle through looks better and CA puts the strength back into the spars.



I am thinking about sheeting the fuselage with 1/32" balsa and making the nose into a fuel proof engine pod. I have bought the sheet already.
I intend to mount the Pee Wee on rubber mounts.



The back plate is resting against a piece of 'good old Irish' Kingspan polyurethane insulation board. It's uber light but dense and stiff. I tend to fill the wing, tailplane, elevator, fin, and rudder between the ribs and spars with sheets of this. I shall build a jig and slice it it my trusty Eclipse (superbly made in Sheffield) coping saw or a hot wire cutter.



Is it sensible to use this?



I think it will end up being a Fairchild AU-23 as the big exhaust will help hide sticky-out bits! And it's nice and grey! I shall not bother with the shark mouth and eyes!



I like grey and yellow things. I even re-painted the orange and black Husky LTH 151 in various shades of grey!




BTW my given name is Dave. Daligh is from my Irish family/clan name: O'Daligh.

Daligh wrote:Thanks Balogh and 1/2A Nut.

Hi Balogh.
Budapest is where my wife, my daughter and myself would have visited this year had it not been for Covid-19. We planed 10 days of canoeing, hiking museum visits and lots of beer and food! Next year with luck!?

I was hoping to find the #281 exhaust throttle for the Pee Wee but had no luck. I thought that I might be able to use the muffler for a similar effect by putting a small hole in the peripheral spring!? I have been experimenting with home made exhaust throttles on the .049. I don't have any machine tools so it's done with hacksaws, files and a Dremel. I throw nothing away and found an old Husqvarna 65L oil tank plug and two 10 thou. shims. After some dermal work, hacksawing and filing I made this test unit. The flange will enable me to drill holes so that the ports align. The bottom shim is opened out to the cylinder thread size. (Some loss of compression, SPI opening and transfer opening) The upper shim to the cylinder OD and it is kinked to act as a friction device.






Your point about tightening the cylinder is very true! I shall have to make a tool to work on the OD of the fins. I made a tool for the glow head as I think the Cox tool is a bit thin!



Hi 1/2A Nut.

The top image is obviously your conversion, is the second image yours as well? If so, very nice. Where do I find a GMark 030 carb? I was thinking of utilising a .049 R/C throttle and adapting it to the Pee Wee tank backplate. I am trying to find a spare back plate right now.

Can you take a couple of measurements of .020 cylinder for me? mm or inches. The O.D. Of the cylinder where the exhaust throttle would be and the height of the throttle when the cylinder is in the crankcase, loosely.
   I made a cheap aluminum version of a .049 throttle, now have several real ones, but I could never find the exact size of copper, brass, or aluminum tube to work with. Aluminum will work and is easy to cut, drill, etc, but I never had the exact size so I used a brass shim. I would prefer brass as it is harder and dissipates heat better, but I need the exact size. The cylinder is trimmed a few thousands of an inch smaller than the regular cylinder if they are the same as the .049 series.

Happydad      

Not very clear! The 4mm is from the upper edge of the lip to the bottom of the exhaust port.

I have made a pin spanner for the Pee Wee head and will make some soft jaws for the 13mm BETA ratcheting ring spanner to use on the cylinder.

It fits the Bee as is but I think the serration would damage it!