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Post  GallopingGhostler Sun Jul 24, 2016 5:07 pm

@rsv1cox wrote:Yes, Thanks George and Kari for the iillustrations.  F4U-1 early model, although it looks more like the 1A with the bubble canopy but minus the "rear windows" so apparent on the model itself.  I bought planking for the wing and should start again on it shortly.

Bob, the one you have is:

Recent engine acquisitions - Page 3 F4u-1_10

You have the scallops for the rear windows similar to the P-40. The designer did a really nice job of mimicking this scale feature on your model.
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Post  rsv1cox Mon Jul 25, 2016 9:54 am

I'm buying it George. My problem is the canopy is so out of proportion to the rest of the air frame. I might just carve another out of a balsa block or make one out of a clear bottle.

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I'm weakening about making this RC, it was designed for CL. Sorry Kari for stepping on your post.

Bob
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Post  KariFS Fri Aug 05, 2016 11:09 am

Wow, a whole bunch of replies that I've missed.

Smooth Bill, Thanks for the info re PAWs. I think I'll test the one with the NVA borrowed from the other and if it is fine I'll order another one from England. Good to know that a separate venturi is not needed.

George, I was not aware that the DHL and UPS fees had skyrocketed. Looks like there is no easy (read cheap) way to ship engines Sad  

Anyway, back to topic, here is my first ever SureStart, got it in the mail today. 15€ shipped, complete with the starter spring. It has never run, hardly been out of the bag (a bit cheesy way to pack engines for sale compared to a jewel case but yeah, cost, profits...) It is not such a "collectible" but it was worth the price in spare parts. Maybe I'll run it, maybe just keep it, I don't know yet.

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Edit: The first pic was a bit dark so I took another one. Not that Y'all hadn't seen a SureStart before but I like clear pictures, no matter how trivial the subject Very Happy
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Post  GallopingGhostler Fri Aug 05, 2016 11:37 am

Kari, that looks like one of the Estes closeouts prior to closing forever. I bought 2 of them in April 2008 for $6.99 US each, UPS shipping then was only $7.99 US. One thing you may want to check for is compression. Estes did not do as good of cylinder to piston matching, some have mediocre compression. Also, from what others say, Estes also did all sorts of weird mixing and matching, so cylinders may vary on how they are ported. The Sure Starts were sport engines anyway, so it's a mute point.

I've found that nylon standoffs can be purchased at a hardware store, so one doesn't have to create a recess in the engine mounting area on the plane to clear the choke tube.

Recent engine acquisitions - Page 3 Dscn2110

Here's my latest acquisition, a 1950's vintage K&B Torpedo .35 CL engine. It came in yesterday, is used but has good compression. After I replace the screws with socket head screws, install missing needle valve ratchet, clean up and paint the head green, clean up the aluminum crankcase exterior will have a good CL engine. This I will mount on the inboard side of the profile fuselage, so exhaust is directed downward away from the hand.

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Post  KariFS Fri Aug 05, 2016 1:50 pm

That's a good looking Torpedo. I guess the exhaust direction was not standardized back then Smile Or maybe it was designed to be mounted upside down? That would obviously require a built fuselage.

I had no big expectations for the quality of this SureStart, but I suppose I got one of the good ones. It has good compression and also the crank end play is rather minimal. So it might make a good runner. I had got these two "late model" engines earlier, probably "pimped" Estes ones as one of them has "not great" compression, and both of them have excessive crankshaft end play. I guess the end play is not a huge problem in tractor use, but in a pusher arrangement it might push the crank pin too far back.

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Those nylon standoffs are a good idea. I was already thinking aluminum blocks, but I'll look for those on the next stop at the hardware store. What are they meant for originally?
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Post  GallopingGhostler Fri Aug 05, 2016 2:03 pm

The nylon stand offs or spacers were found in the special hardware section of a local home improvement center store. Back in the time that the Torpedoes were made, CL flying direction wasn't standardized yet, some flew in a clockwise direction. Then a left mounted engine would be on the outboard of the circle. As time went one, we see that all engines reverted to right hand exhaust. Also, many CL planes mounted the engines upright or upside down, until profiles became more popular. On a profile fuselage, one could revise the nose to make the engine upright. I'm opting instead to simply mount the engine inboard, less work.

I don't know if installing a brass drive plate would mitigate some of that end play. I suppose one could adapt a washer that fits over the crankshaft, sufficiently filed to be thin enough to act as a shim and bearing for pusher use.
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Post  KariFS Tue Aug 16, 2016 10:37 am

Today I received my first Cox car engine:

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Any idea about what kind of a car this is from?

The seller had been rummaging his father's old hobby stuff and among some pile of electric car parts there was this and he said he immediately thought of me Smile I had bought two PAW diesels, a TeeDee 051 and a Babe Bee from him earlier.

This engine looks intact, no major scratches or other damage nor any missing parts that I can think of. Of course it is gunked solid so I'll need to take it apart to clean it. How should I proceed and is there anything particular to look out for? I have once taken a lawnmower pull start apart, it was a heck of a job to put it back together... I'd rather not have this one shoot its internals around the den lol!




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Post  OVERLORD Tue Aug 16, 2016 1:04 pm

Kari, the pull start and clutch assembly is not difficult to dismantle. I recently changed the crankcase on my Jerobee Corvette engine without any probs. When removing the trumpet shaped piece , you will see the one way clutch to drive the crankshaft when pulling the cable. The main disk is about 1 mm thick and in both recesses you'll see 2 round metal plates of about 5 mm diameter. Normally, they will stick due to an oïl film. Be careful not to loose these 2 parts. Remove them and put them away. Around the crankcase end, you will then see a circlip that holds the grey plastic starter unit in place. After removing the circlip, the cassette with cable and spring sitting over the crankcase nose pulls off easily without the steel watch spring or cable unwinding. If needed, Matt sells crank cases and crankshafts for car engines.

Lieven
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Post  KariFS Wed Aug 17, 2016 8:26 am

Thanks for the encouragement and advice Lieven!

Yesterday evening I spent an hour or so looking for my "non-metric" hex key set so that I could loosen the bolt on the end of the crankshaft. Found all my 3 metric sets and several loose metric keys but the one I needed is still somewhere DAMMIT! Need to stop by at the auto parts store today to pick one up, that will be the easiest way to get the lost one to show up too.

Looks like the clutch "bell" (the brass part) is slightly warped, less than a millimeter but still. Not sure how it would affect the operation, but this one will most likely become another display piece so it doesn't matter much. I may test run this one shortly if it looks OK from the inside.

I'll post pics once I get it disassembled.

Any idea what kind of a car this is from? A short integral tank seems a bit strange for an R/C car, should it have a horseshoe backplate or a longer (or drilled?) tank?
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Post  roddie Wed Aug 17, 2016 11:24 am

It could possibly have been in this "Trike".. Huh... It seems that most other gear-driven (non-worm gear..) models did not have the recoil starter.

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Post  KariFS Wed Aug 17, 2016 1:23 pm

Well that chopper trike reads about 9.5 on my Far-Out-O-Meter lol!
Never seen even a pic of one before.

I thought my engine was from an R/C model because of the centrifugal clutch and the exhaust throttle but I suppose it isn't necessarily so. The 5cc tank would give a pretty short running time for the engine, so maybe it is for a free-rolling model after all.
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Post  balogh Tue Aug 23, 2016 2:22 pm

I bought these 2 engines from a UK ebayer, and they just found their new home here after delivered by the postman today....paid altogether 19,1 UK Pounds for the 2 plus the engine mount (plus shipping cost that was not too much given the shipment within Europe).
I guess it was a good deal.

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I cleaned them and gun-blued the abuse-spots on the cylinders, added a new berillium reed to the Black Widow, and tried to identify their birth dates based on the COX Model Engine Handbook of Dan Sitter.

I particularly like the very slim and light, red postage stamp backplate production engines, this type - with a 2-bypass No 1 cylinder though -  was actually the COX engine I  first met in my life back in 1974, powering a COX Stuka (and fell immediately  in love with, and kept well preserved in my COX inventory). It features a No 2 thin wall cylinder with a single bypass (not a muscle engine, though), as well as a 3 piece piston (older pistons had the socket not machined from the piston itself but swaged as a separate item into the cylinder crown),  and narrow neck nose on the crankcase... details putting its birth date to somewhere between 1961 and 1968...very small running hours probably, leaving the engine with excellent compression.


The Black Widow features a No. 1 stepped wall cylinder, a 3 piece piston and a metallic backplate, very hard to find these days...with these details it must be an early version born around 1973 but definitely before 1985 when the thick wall cylinder appeared on Black Widows. This engine has superb comression, but looks to have more hours on it than the production engine above, and came mounted on a light metal engine mount for Free-flight planes, as shown...I have never had one before, maybe I will build a larger sail plane to power it.
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Post  duke.johnson Tue Aug 23, 2016 2:32 pm

A buddy of mine who owns the LHS gave me these engines last week from a pile of modeling stuff from a local club members estate.
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And I assumed this one was a boat motor of some sort.  
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I guess I'll have him look for the front end.  Thanks for posting.
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Post  balogh Tue Aug 23, 2016 2:55 pm

@GallopingGhostler wrote:.......
I've found that nylon standoffs can be purchased at a hardware store, so one doesn't have to create a recess in the engine mounting area on the plane to clear the choke tube.

................

You must know this Surestart engine mount, do you? Seems to be a more rigid, customized mount than the plastic stand-offs.

http://coxengines.ca/cox-.049-engine-firewall-helicopter-mount.html
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Post  getback Tue Aug 23, 2016 2:57 pm

Good looking engines André's yes the BW you show is difficult to find , I have had a few widows but now am down to 1-2 most were just passing through Sad cant keep them all unfortunately Laughing You going to RC that Baby? or just admire it ?
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Post  balogh Tue Aug 23, 2016 3:05 pm

Eric,

I  will probably bench-run both tomorrow to check how they preserve compression when hot...engines in good condition keep their compression even then.

I will probably use the BW on a RC plane, mounted on the pod...this will help me mount a key-chain camera also in the nose of the plane without castor-smearing the lens like with most of my RC planes COX powered in their noses, though.

I will probably beef-up the postage stamp Bee with a high-comp head and then swap it with my TD Reedie currently powering my Lil Roughneck RC plane..The No 2 single by-pass cylinder itself is not famous for its brute force.

Sometimes I feel like a prodigal son having 60+COX engines, many New in Box, and sitting there just for my pure admiration...I will probably never start up many of them in the rest of my life...
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Post  GallopingGhostler Tue Aug 23, 2016 7:08 pm

@balogh wrote:
@GallopingGhostler wrote:I've found that nylon standoffs can be purchased at a hardware store, so one doesn't have to create a recess in the engine mounting area on the plane to clear the choke tube.
You must know this Surestart engine mount, do you? Seems to be a more rigid, customized mount than the plastic stand-offs. http://coxengines.ca/cox-.049-engine-firewall-helicopter-mount.html

Hello Balogh. Yes, I am familiar with that mount. Personally, the nylon spacers were cheaper and have adequate contact area for stable mounting of the engine.

Latest acquisition from a CL friend, Bro. Dane Martin as a gift; a brand new and un-run OK Cub .049R engine.

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Post  KariFS Tue Aug 30, 2016 12:34 pm

Is that a really big hand or a really small engine?

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Well, maybe a bit of both Smile Finally I got my hands on one of these This Site Rocks!  It could use a bit of a clean up and a new carb body but otherwise it is nice and suits my collection very well. Now I have at least one example of all the different TeeDee sizes except for the .09. Not many of those around.
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Post  GallopingGhostler Tue Aug 30, 2016 1:18 pm

@KariFS wrote:Is that a really big hand or a really small engine? Well, maybe a bit of both Smile Finally I got my hands on one of these This Site Rocks!  It could use a bit of a clean up and a new carb body but otherwise it is nice and suits my collection very well. Now I have at least one example of all the different Tee Dee sizes except for the .09. Not many of those around.

That is a sweet looking little .010 Tee Dee you have in your hands, Kari. That faded red plastic can be cleaned up to its bright red colour with a little effort. Thumbs Up

And I stand corrected, the engine I recently got is an OK Cub .059R or .06R (OK used both designations). It should have the power of a Babe Bee and perhaps a little more. Very Happy
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Post  KariFS Tue Aug 30, 2016 1:25 pm

@balogh wrote:I bought these 2 engines from a UK ebayer, and they just found their new home here after delivered by the postman today....paid altogether 19,1 UK Pounds for the 2 plus the engine mount (plus shipping cost that was not too much given the shipment within Europe).
I guess it was a good deal.

It was a good deal. I would like one of those early BW's in good condition myself. I have one like yours but it is with a silver tank and the anodizing on the crankcase is a bit worn. Nice and charming runner but not exactly a showpiece. My other BW is a never-run late model (not an Estes) but that's with a plastic backplate and a hex drive plate, neither of which are my favorites.

Is that engine pod plastic or aluminium? Any markings on it? Looks like it would make a nice display stand for a tanked engine if you mount it on a piece of wood.
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Post  Marleysky Tue Aug 30, 2016 3:34 pm

@duke.johnson wrote:A buddy of mine who owns the LHS gave me these engines last week from a pile of modeling stuff from a local club members estate.
And I assumed this one was a boat motor of some sort.  
Recent engine acquisitions - Page 3 1_moto10
I guess I'll have him look for the front end.  Thanks for posting.

Hey Duke,  my quess is that may be a car engine, not a boat. Could be any application that used the friction fit flywheel.   If you want to use it for an airplane, Matt at ex model engines has a perfect fitting prop driver to fit on there:  http://www.exmodelengines.com/product.php?productid=18246&cat=266&page=1

Reasonably priced too!
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Post  balogh Tue Aug 30, 2016 6:17 pm

@KariFS wrote:
@balogh wrote:I bought these 2 engines from a UK ebayer, and they just found their new home here after delivered by the postman today....paid altogether 19,1 UK Pounds for the 2 plus the engine mount (plus shipping cost that was not too much given the shipment within Europe).
I guess it was a good deal.

It was a good deal. I would like one of those early BW's in good condition myself. I have one like yours but it is with a silver tank and the anodizing on the crankcase is a bit worn. Nice and charming runner but not exactly a showpiece. My other BW is a never-run late model (not an Estes) but that's with a plastic backplate and a hex drive plate, neither of which are my favorites.

Is that engine pod plastic or aluminium? Any markings on it? Looks like it would make a nice display stand for a tanked engine if you mount it on a piece of wood.


Kari it looks to be a very light metal pod, a kind of aluminum alloy but I wonder who and how made it because it does not look like an industrial production, but rather, as a home made one. But it really is a good one.

The BW still needs some more attention as it does not run faster than, say, 17k on a 4,5x4 prop, while the li'l No2 cylindered postage stamp backplate production engine has already run beyond 18,5k with a insert type head.Both have excellent compression, and I added a mylar reed to the postage stamp backplate as well.
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Post  GallopingGhostler Tue Aug 30, 2016 7:58 pm

@balogh wrote:The BW still needs some more attention as it does not run faster than, say, 17k on a 4,5x4 prop, while the li'l No2 cylindered postage stamp backplate production engine has already run beyond 18,5k with a insert type head. Both have excellent compression, and I added a mylar reed to the postage stamp backplate as well.

How's the amount of thrust produced on the BW with smaller diameter props? Reason why I ask is that at sea level, 20 years ago I found the difference between a 5.25x4 and 6x3 prop negligible, they both produced about the same amount of thrust with my Airtronics Q-Tee. But at 6,500 feet (1,981 m) elevation, the 5.25x4 barely lumbered along, but with a 6x3 or 6x4 produced more thrust and it flew with authority. This was using Sig Champion 25% nitro fuel with 20% oil.

This is the following write up in August 1974 Aeromodeller. Sceptre Flight: Black Widow Engine Test

Peter Chin wrote:The Black Widow is intended for operation on fuels of a medium nitro rating - i.e. about 15 percent nitromethane. Using such a fuel, our test motor recorded a maximum torque of just over 6 oz.in. at around 9,000 r.p.m. and a peak output of nearly .08 b.h.p. at between 15,000 and 15,550 r.p.m. These are quite good figures for a 'sport' type .049 and are reflected in some useful speeds on various props.

The most useful prop sizes with the Black Widow should be 6x4 for a control-line stunt or sport and a 6x3 or 'fast' 6x4 for free-flight although, should the need arise, the engine is capable of turning 7 in. diameter props of 3 to 4 in. pitch, such as one might wish to use for a large 'motor-glider' type model for example.

Prop speeds recorded on test include 10,600 r.p.m. on a 7x4 Taipan nylon-glassfibre, 11,200 on a 7x3-1/2 Bartels epoxy-glassfibre, 12,000 on a 7x3 TopFlite wood, 12,600 on a 6x4 Tornado nylon, 13,000 on a 6x4 TopFlite nylon, 13,800 on a 6x4 McCoy nylon, 13,900 on a 6x3 KeilKraft nylon. 14,000 on a Tornado nylon, 14,600 on a 6x3 TopFlite nylon and 15,500 on a 6x4 (nominal) D.C. nylon. The Black Widow was also checked on a 5-1/2x3 and 5x4 Tornado nylon props but these took it up to over 16,000 r.p.m. static which probably means rising to 17,500-18,000 in flight and, as the b.h.p. curve indicates, there would be no advantage in propping the engine for more than say, 16,000 in flight. No problems were encountered during the tests of this new Cox model and the original Cox glowhead survived the entire series of test runs.

Of course some are running modified BW's with alternate cylinder / piston & glow head combinations, and on hotter nitro mixtures, which would of course alter the results from what Mr. Chinn expressed.

Just curious, of other's experiences, inquiring minds want to know. Laughing lol! I Love This Forum! Wink
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Post  balogh Tue Aug 30, 2016 8:10 pm

@GallopingGhostler wrote:
@balogh wrote:The BW still needs some more attention as it does not run faster than, say, 17k on a 4,5x4 prop, while the li'l No2 cylindered postage stamp backplate production engine has already run beyond 18,5k with a insert type head. Both have excellent compression, and I added a mylar reed to the postage stamp backplate as well.

How's the amount of thrust produced on the BW with smaller diameter props? Reason why I ask is that at sea level, 20 years ago I found the difference between a 5.25x4 and 6x3 prop negligible, they both produced about the same amount of thrust with my Airtronics Q-Tee. But at 6,500 feet (1,981 m) elevation, the 5.25x4 barely lumbered along, but with a 6x3 or 6x4 produced more thrust and it flew with authority. This was using Sig Champion 25% nitro fuel with 20% oil.

This is the following write up in August 1974 Aeromodeller. Sceptre Flight: Black Widow Engine Test

Peter Chin wrote:The Black Widow is intended for operation on fuels of a medium nitro rating - i.e. about 15 percent nitromethane. Using such a fuel, our test motor recorded a maximum torque of just over 6 oz.in. at around 9,000 r.p.m. and a peak output of nearly .08 b.h.p. at between 15,000 and 15,550 r.p.m. These are quite good figures for a 'sport' type .049 and are reflected in some useful speeds on various props.

The most useful prop sizes with the Black Widow should be 6x4 for a control-line stunt or sport and a 6x3 or 'fast' 6x4 for free-flight although, should the need arise, the engine is capable of turning 7 in. diameter props of 3 to 4 in. pitch, such as one might wish to use for a large 'motor-glider' type model for example.

Prop speeds recorded on test include 10,600 r.p.m. on a 7x4 Taipan nylon-glassfibre, 11,200 on a 7x3-1/2 Bartels epoxy-glassfibre, 12,000 on a 7x3 TopFlite wood, 12,600 on a 6x4 Tornado nylon, 13,000 on a 6x4 TopFlite nylon, 13,800 on a 6x4 McCoy nylon, 13,900 on a 6x3 KeilKraft nylon. 14,000 on a Tornado nylon, 14,600 on a 6x3 TopFlite nylon and 15,500 on a 6x4 (nominal) D.C. nylon. The Black Widow was also checked on a 5-1/2x3 and 5x4 Tornado nylon props but these took it up to over 16,000 r.p.m. static which probably means rising to 17,500-18,000 in flight and, as the b.h.p. curve indicates, there would be no advantage in propping the engine for more than say, 16,000 in flight. No problems were encountered during the tests of this new Cox model and the original Cox glowhead survived the entire series of test runs.

Of course some are running modified BW's with alternate cylinder / piston & glow head combinations, and on hotter nitro mixtures, which would of course alter the results from what Mr. Chinn expressed.

Just curious, of other's experiences, inquiring minds want to know. Laughing lol! I Love This Forum! Wink

Unfortunately I am not equipped to measure thrust, but in my experience if you use the very prop on any COX engine that allows it to run near the rpm corresponding to the peak brake horsepower on the performance curve, the useful power of the engine will be maximum. There is no use in over or underpropping an engine as it is always the brake horsepower max that you want it to run at. The useful power of the engine is calculated as the product of thrust and airflow velocity (P= Fxv) whereas the thrust balances with the drag of the plane at a given velocity,  meaning this will also result in the highest speed of the plane you mount the engine to. (The drag force of the plane is proportional with the quadrate of its velocity F=Axv2, so at the end the Power of the engine is equivalent with P= Ax v3 where A is a constant belonging to the airplane. Thus the max engine power will mean max plane velocity, which of course is a no-brainer)

For the BW the relevant rpm (under test conditions) for max. brake horsepower,  is around 17k, as per the 1974 test measurement published in Aeromodeller, see the link attached.
http://www.mh-aerotools.de/airfoils/cox_frameset.htm


Last edited by balogh on Wed Aug 31, 2016 3:38 am; edited 1 time in total
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Post  GallopingGhostler Wed Aug 31, 2016 1:07 am

@balogh wrote:For the BW the relevant rpm (under test conditions) for max. break horsepower,  is around 17k, as per the 1974 test measurement published in Aeromodeller, see the link attached. http://www.mh-aerotools.de/airfoils/cox_frameset.htm

Are you sure that you may have mistaken the Medallion .049 curve for the BW?

http://www.mh-aerotools.de/airfoils/cox_performance.htm

Recent engine acquisitions - Page 3 Cox_performance_2

Curve shows the BW peaking around 15,500 rpm. Medallion .049 is peaked around 17,500 rpm.

Also, I've found the Cox reed valve engines to be torquey buggers. Even the diminutive .020 Pee Wee would turn a Top Flite 5.25x3 nylon with same flight speed as Cox 4.5x2 plastic prop, but give me about 1 more minute in flight due to its lowered rpm. BW is torquey, too. From Peter Chinn's numbers, a T/F 7x3 wood prop turned at 12,000 static. Figuring in the air would be turning at least 13,000 rpm, which would put it within a Watt or two of peak. These are indeed very good sport motors.
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