Testors 049

Ian, A nice 3D printer project would be to re-design a rear-end for those little engines. The reed holder/seat would be the most critical part I think? Most people don't use them because you can't easily mount them in anything.

As for the "unobtainable" glow-heads... I wonder if anyone has tried to mill the top of a burnt plug and drill/tap it out for a 1/4 x 32 thread standard glow-plug? It works with the Cox version. Maybe not possible, because the Testors design is a lot shorter?

I have one.. I have never run it. I just decided to take it apart this afternoon, because it was stuck. I found that it been previously run by someone..  and there was a burr inside the cylinder near an exhaust port. The piston did not appear scored though. I took a tiny round file to the cylinder (lightly) and smoothed out the burr.

The reed is a star-shaped transparent-orange mylar type. I removed it, cleaned it and re-installed with the circlip and it operates fine.

The glow-head gasket in mine was a non-ferrous (Aluminum?) type.. which measured .031" thick!!! A Cox .049 gasket is .005" thick by comparison. The two types are very close to the same size otherwise. Compression didn't seem great with the thick (stock?) gasket.. so I installed x1 Cox gasket. The compression seems better.. and the piston does not bind. This would be .026" less gasket thickness than what "was" in there.

I'd like to run it.. but I don't really have a way to mount it securely... a common problem with these.

Ian's as you can see; has a different back-plate than mine does. Did Testors use a "press-in" vinyl-type fuel-line in the hole just behind the needle.. or am I missing a fitting?

I have two 4-blade props that fit this engine. I suspect the prop-shaft is 6-32 threaded, because Cox props are too small.

Oldenginerod wrote:

roddie wrote:
Ian's as you can see; has a different back-plate than mine does. Did Testors use a "press-in" vinyl-type fuel-line in the hole just behind the needle.. or am I missing a fitting?

If you're talking about the type of tank pictured, it just pops straight off with a bit of a pull.  Unlike the series 8000 engine which Ian first pictured, which has a lug to locate the tank in one position, the Fly-em engines like yours are free to spin and are orientated bu sitting firmly clamped in the fuselage.  To answer Roddie's question, the hole beside the needle valve in the Fly-em style fuel tank is actually the air intake.

Rod.

Thanks Rod.. but I'm still a little confused. The rear-end on this engine seems to be more like a Cox 290 prod. engine backplate (in function).. and would use an external tank, wouldn't it? It's just not large enough to hold a significant amount of fuel for any type of model. I would think that the fuel tank for this Testor's "Prod. engine" (as with the later Cox RTR models) would have been a separate one mounted in the model, with fill/vent nipples/holes.. on the top of the fuse's nose.

I would guess that the "square" opening at the back is for air-intake.. however I can't see any sort of a "mesh-screen" to keep debris from fouling the reed.

Here's a few photos I took.. which "might" depict this particular engine being installed in an "inverted-cylinder" orientation in an airplane... with the back-plate turned so that the needle protrudes out the lower outboard side of the fuse, the "fuel-line" (which probably would have been a stiffer clear-vinyl type) "pushed-into" the hole next to the needle.. and the "square" air intake (at the rear...) facing "down".. for less chance of dirt/sand being able to enter. The single "mount-rail" on the case would have been on the "inboard" side of the fuse.. and out of the way of fuel-line maintenance. It's just a theory... but makes sense to me.





Unfortunately.. this engine; unlike the Cox prod. engines, has no crankcase screws securing it's backplate.. making mounting in any other model except the one it was produced for.. virtually impossible.

anm2 wrote:

roddie wrote:

Oldenginerod wrote:

roddie wrote:
Ian's as you can see; has a different back-plate than mine does. Did Testors use a "press-in" vinyl-type fuel-line in the hole just behind the needle.. or am I missing a fitting?

If you're talking about the type of tank pictured, it just pops straight off with a bit of a pull.  Unlike the series 8000 engine which Ian first pictured, which has a lug to locate the tank in one position, the Fly-em engines like yours are free to spin and are orientated bu sitting firmly clamped in the fuselage.  To answer Roddie's question, the hole beside the needle valve in the Fly-em style fuel tank is actually the air intake.

Rod.

Thanks Rod.. but I'm still a little confused. The rear-end on this engine seems to be more like a Cox 290 prod. engine backplate (in function).. and would use an external tank, wouldn't it? It's just not large enough to hold a significant amount of fuel for any type of model. I would think that the fuel tank for this Testor's "Prod. engine" (as with the later Cox RTR models) would have been a separate one mounted in the model, with fill/vent nipples/holes.. on the top of the fuse's nose.

I would guess that the "square" opening at the back is for air-intake.. however I can't see any sort of a "mesh-screen" to keep debris from fouling the reed.

Here's a few photos I took.. which "might" depict this particular engine being installed in an "inverted-cylinder" orientation in an airplane... with the back-plate turned so that the needle protrudes out the lower outboard side of the fuse, the "fuel-line" (which probably would have been a stiffer clear-vinyl type) "pushed-into" the hole next to the needle.. and the "square" air intake (at the rear...) facing "down".. for less chance of dirt/sand being able to enter. The single "mount-rail" on the case would have been on the "inboard" side of the fuse.. and out of the way of fuel-line maintenance. It's just a theory... but makes sense to me.





Unfortunately.. this engine; unlike the Cox prod. engines, has no crankcase screws securing it's backplate.. making mounting in any other model except the one it was produced for.. virtually impossible.

Roddie,  The white "backplate" is actually the gas tank.  The square hole in the back is the fill tube.  The round hole that sits right by the needle adjustment is a vent hole.  On the series 8000 engine, I have primed the engine from that hole, and it has worked perfectly.  Much better than the surestart snorkel.  I have run a couple of the Series 8000 engine, and they run great.  I see them on ebay frequently and you can pick them up Brand New for about $20 + shipping if you are patient.  Frankly, they are worth the money.  The series 8000 engine is suppose to be very powerful.  About like a black widow.  I got that information from an engine test article.  Check it out here:

http://sceptreflight.net/Model%20Engine%20Tests/Testor%208000%20(2).html

BL:  Easy starting and powerful .049 engine.  Also, a "revolutionary" piece of 1/2a history.  From my perspective, a must have if you collect 1/2a engines.  At $20 for a brand new engine - basically a steal. Andy

Thanks Andy, Gee.. that tank couldn't hold much more than 2-3cc's of fuel.. but I guess that's enough for a short blast! Might make for a fun experimental "speed model" engine!

Oldenginerod wrote:Roddie.
The engine you show is from the "Fly'em" series of RTF planes, so they were only ever designed to mount in the airframe they were sold with.  The cylinder sat at about 45° down outboard, the square fill tube sat straight up and the needle was about 45° up inboard.  The planes came out with very short dacron lines so a short run was desirable, although my P-40 certainly never broke any speed records.  I recall the tank probably giving about 2 minutes flight time.
There were some Testors models which used a similar "pipe bomb" engine but had a front rotary valve.  The rear clip-in tank was separated from the crankcase (no reed valve/intake) and there was a fuel metering tube running along the side of the crankcase from the tank to an intake opening forward of the cylinder.  (Not a very good explanation).  Best to go to the 049 collectors group site and have a look at the photo gallery.  These engines were not at all successful due to a very dodgy stepped fuel regulator, as opposed to a true needle valve.

Rod.

Thanks Rod. This is clearing up a lot of questions that I had on the engine that I have... as well as others that may become available to me. The front rotary-valve version that you mentioned; would seem to have only operated "successfully" on Testors fuel-blend.. not having a needle-valve. Would this be correct?

"Galloping Ghostler".. your CG "Swordsman" looks fabulous! This was my first balsa glow-powered airplane! What particularly caught my eye on yours.. is the color. My dad built mine for me (circa 1969) with a similar "green" on the wings/tail-feathers.. and the fuse was "black".. with a Babe Bee for power. It would be fun to have a CEF "Carl Goldberg" model event of some kind. There were so many decent performing control-line models through the years.. in various sizes/classes.. along with AMA NATS champion endorsements! The fact that Brodak continues to "repro" some of the CG kits, is testament to their popularity.

Oldenginerod wrote:Apparently the fuel metering valve they used had 5 or 6 steps to adjust the mixture rather than an infinitely variable adjustment like a needle valve.  The original test pieces apparently worked very well, but when it came to full scale production, the moulding procedure led to some major inaccuracies in the valve and they were a dismal failure.  My example is missing the valve, but you can see in the picture that a tube runs along the side of the crankcase in the "mounting" channel, ending at the intake hole on the right.  Probably worked a bit like an emulsion tube in an automotive carb.

...as opposed to the type we've been discussing.

This last one is my favourite.

The rear mount clips in the same way as the tank does on the other models and incorporates a reed valve like the one in the second picture.  The mylar reed is retained by a clip-on plastic retainer, not unlike the later Cox design.  There is a clip-in venturi (missing in this example) incorporating the spray-bar and needle valve for using a separate fuel tank.  I have one with the venturi and one missing.  I plan to epoxy in a venturi from an old Cox plastic back plate.  The mounting pattern is identical to a Babe Bee and I believe the engine was exclusively used in the Testors Galax IV Hovercraft.  It would make for a really simple comparison test, being able to bolt it onto a plane with known capabilities in place of a Cox engine.

Rod.

Really neat stuff Rod!! It almost seems like the "Testors/McCoy story" is not unlike the acquisition of Cox by Estes? Glow engines weren't their primary concern.. or their forte'.. but they did try to compete with the "Big-Boy" glow-engine producers of the day.. except they were lacking the engineering/R & D.. to have their products be successful.