Stuka Stunt Main Forum · 46 of 46 known posts recovered
I plan to but it in a Brodak Baby Flite Streak for Classic flying.
Looks great! Are you planning a diesel version of this engine? (Just kidding).
Galbreath/Nelson #1 (also available from Kitting it Together, I hear)
Norvel retainer/Lite Machines or Glo-bee #2
Norvel Freedom #3
C*x High Compression #4
C*x regular #5
Anybody's Short Plug conversion #10 (there are no #6 - #9)
In the above comparison there seems to be at least 200 rpm per step after setting the correct compression with gaskets. (No, there is NO easy way to find out, you have to do the runs with a tachometer)
Anyway, for this engine, the Norvel is just fine, and no need to go nuts for power on an engine I want to last a long, long time.
Yup, Larry does sell them.
Any comments as to 1) The similar (possibly no longer available) Kustom Kraftsmanship head, and 2) the Galbreath head used with the different plugs available - Nelson makes 3 varieties including the two part flat coil version the pylon racers like, and Jim Booker makes one:
http://www.cedarcomm.com/~fly/Catalog.htm#glow%20plug
Incidentally, it looks like Jim Booker also sells the tap and the tap drill needed to form the threads and seat for a Nelson plug. Might be worth getting to convert all those blown out Cox 1702s I've collected over the years..
>Norvel retainer/Lite Machines or Glo-bee #2
>Norvel Freedom #3
That's interesting to know. I didn't realize the Lite Machines plug was different than the Norvel Freedom Plug.
The Lite Machines plugs have the flat spiral element instead of a coil. They were a copy of the Glo-Bee, and, so far as I know, are no longer made 
Rob Johnson
Orange,Ca.
Cool!...
Jake
That engine is just crying to be flown on a red, white and blue Baby Flite Streak on the Fourth of July.
Tom
The Space Hopper was a reed-valve engine that was introduced a few years ('58 or '59 I think) before the Tee Dee ('61) The Thermal Hopper (rear-reed induction, cast crankcase) was a predecessor to the Space Hopper whose crankcase was machined from an extrusion.
Wish I had a couple of each! 
I have a Thermal Hopper. The TH was a "radial" mount job while the Space Hopper used beam mounts. Cox made a nifty little stand-off type "spool mount" for the TH so you could mount it on a firewall without making a hole in it for the venturi.
Interestingly, these reed valve Cox motors (at least the rear intake reed valve design idea) were copied overseas by both the Russians (Mk-17) and East Germans (Jenas), I have heard that they believed that if Cox used this design, it must be the way to go. Jena also made rear rotor diesels too...
Jake
George
Jake
I have 2 each Thermal Hopper, original Babe Bee, Space Hopper, Space Bug, Holland Hornet, Atwood Shriek, Holland Wasp and RR-1.
Of course paying the guards is making me go broke... 
"All we own, we owe!
All we own, we owe!"
From the marching chant of the Wicked Witch of The West's guardsmen in the Wizard of Oz.
Jake
I have a red yellow, and natural tank SB Jr. ... so there!
...But I don't have a Space Hopper or an RR1. 
George
That version of a "Hopper" never crossed my consciousness. It must've come & gone very rapidly and made a small splash as it did so.
.
Kiwi
**
She looks pretty nice all in one piece!! It should really sing too.
Take care,
Tim Wiltse
That is correct. At least it certainly was in my case, and I tested several of them. Consistently less power than Galbreath head.
I've lost track of the various sorts of glowheads out there, but at one time AME was selling a pretty good plug which required a clamping ring. These were (are?) nothing more than what at least used to be the standard 2.5 Ruskie glow heads used in all manner of glow engines before they could get the good stuff, i.e. Nelson plugs. They are merely remachined to fit in a 1/2A engine. I've probably still got a couple hundred of the things as produced, not yet resized for 1/2A motors.
Dan
I also have a couple of the old Russian Typhoon F2D engines with the bifurcated exhausts that use the Russian integral head plugs (but also came with a standard plug head). Integral heads would have been a pain in the neck if you needed to change one during a match. Also some old Russian long reach plugs. Some had welded on idle bars which I was told to pry off before using, otherwise they might come off in the engine. The elements were supposedly prone to coming loose, too.
Some of the new Russian motors take the Rossi Turbo plugs (same idea as the Nelson, different size, usually for cars). Not sure why - Rossi Turbo plugs cost 2-3X what a Nelson does. The F2A engines use a different kind of button plug altogether.
Hey Tom, don't you live right down the road from me? Concord right?
John
Yup that's me. Not knowing where in H-burg you live but I bet we could stand on the roofs of your houses and see each other!!!
Later,
Tim Wiltse
You may have missed one item I didn't mention. I used the Venom/Killer Bee drive washer and stainless steel barrier washer so I can use an electric starter. You can actually see it if you look at my photo.
Did I mention that I also use the stainless steel reeds?
I am not an engine collector, I just don't seem to get rid of things I am not using....
You went the "easy" route? You will see (excuse the dust particles) a hard steel washer behind my "stock size" drive washer also ..... this washer was made from a set of cheap Walmart feeler gauges. I use these various feeler gauge leafs a lot in making specialized spacers, shims, or washers to any desired thickness. My Space Hopper has been tached at well over 22,000 RPM .... this with 5-3 Cox gray prop, high nitro, and Glo Bee insert head.
I have not tested the SS reeds in high performance mode yet ..... they are great for normal use, but I hear they are too heavy for high RPM running? The original Beryllium Copper reed is the only way to go in my opinion. Have you tried the laser cut three legged reeds?
Later,
Tim
When we developed the stainless reed, we tried several thicknesses, and materials. What is in there worked the best. It was a surprise to me, but thinner material didn't run as fast.
I never had much luck with the teflon reeds, the ones I have seen start out warped. Perhaps they flatten with use, but I didn't have that much patience.
The Killer Bee that I had on a 1/2A Spacer would easily top 22K. And that with the SST reed.
However, the one sure and permanent rule in this hobby is to use what works for you. Listen, learn, try, but go with what actually functions the way YOU want. After all, we have been assured by "experts" that tuned pipe airplanes could not perform above 45 degree angles, 4-stroke engines are "Pond Scum" and also I was assured by a VERY famous Nats champion that no 4-stroke would ever win a major contest. One of the reasons was that they don't use enough fuel, so you couldn't control the engine run time accurately. (ever heard of a calibrated syringe?).
Oh well, I am sure we could have an entire thread on "You can't do this" horror stories. It might even be fun to dig up all the dirt.
Larry,
First, I am always amazed at the number of responses you get to small-bore engines and related topics.
Secondly, are you baiting me into a slug fest of some sort? As always, I'd love to beat you severely about the head and shoulders, especially about "you can't do this" horror stories.
Dan
P.S. Four-strokes are pond scum. The fact that I am currently flying a couple of them should not detract from previously-published--mostly humorous--comments.
Why shouldn't I get lots of attention about small stuff. It is FUN! Frustrating, maddening, tear your hair out, but fun for all that.
In good weather, a really good .061 model can turn in as good a pattern as anything bigger. The only excuse for damaging your wrist, elbow and shoulder joints is that big, big airplanes don't bobble in the wind (but they do crash, as shown at this year's Nats).
Besides, aren't you the guy who first brought the VA and AME engines into this country?
BTW, what prop was you running on the 22,000 plus RPM Killer Bee?
I bought a pair of black widows at a swap meet once, took them home - and then discovered neither had reeds. I cut a pair out of drafting mylar, and they seemed to work OK.
So I take it Estes/Cox now sells stainless steel reeds? Hmm.. Maybe I should get a few.
Could you give us a few details about it? Things like how are the 2 crankcases joined - threaded together? Does it have stock reedie crankshafts connected together, if so how? How did you do the cylinder threads on your crankcases? What kind of reed housing design and reeds did you use? Inquiring minds (at least mine anyway) would like to know.I just got a lathe and have been trying to come up with a unique looking engine design to play around with using Cox parts. Yours is one of the "unique-est" I've ever seen!
John
As much of this thread has turned to reeds and their control, or lack thereof, over gases passing into an engine, have you kept current with the reeds and supporting reed blocks which have been commonly used in two-stroke motorcycle engines for many years?
Back when my responsibilities including providing design specifications for various model aircraft motors I was always intrigued by the (potential) use of reeds. While nothing of substance every came of it, I thought a reed block and petal-type reeds fitted to the rear cover of a 60 would be pretty cool. No big windows cut in the crank. Needle moved to the rear, away from prop. A vacuum in case results in flow. Pressure closes the reeds. Various materials to control amount of opening, when reeds opened. Doublers and triplers to fine tune.
(Note: No one ought to confuse above as indicating that I am in any way an engine designer. Providing simple specs such as, "I don't care if it makes the engine heavier, the VA .049 *will* in fact be designed so as to replace *this* engine," and kicking in with off-the-wall ideas from other disciplines in no way qualifies me as a designer of engines.)
While initial specs for AME were provided by Da Dirt, and I was the first to bring in big bags of prototype parts/pre-production parts, there was a blow-up of sorts. I terminated my relationship with designer and his group, they sold the tooling to another company. I never actually imported production AMEs.
Dan
There is a group of us on RCU that are "hardcore" 1/2a'ers. I myself have been working on both rear disk and rear drum rotor Cox conversions. I know another fellow that has built a v-block reed holder like that from a bike!!!That's the good thing about .049's they are small and cheap to work on.
Later,
Tim
There was a thread on RCUniverse where either AJCoholic or Japanman made a block type reed system for a C*x engine. That looked really neat, and I can see how it would work more positively and at higher rpm than a standard C*x reed system.
The original C*x engines used a positive shut reed system in the Space Bug and Thermal Hopper series. A reed and a doubler entrapped for positive shut-off, with a tab to limit the flex. What a pain to assemble!
I find the APC 5.5-2 prop has way less load than the Cox 5-3 gray prop, if you know what I mean? That being said, I wonder what is the top end limit of reed valve RPM .... I mean the reed must have a limit where it will simply start "floating"? I've never found this limit, have you? I think maybe the highest reed valve RPM I have seen on the tach is around 23,500 to best of my memory .... just how high is the top end RPM limitations of reed valve induction I wonder?
Another question NO ONE has been able to answer is this: I wonder what is the intake timing numbers on a reed valve engine .... by this I mean at what point or degree on the c'shaft does the reed open, and then close? For instance on a 1/2A Tee Dee front rotory valve engine the crank opens at about 45 degrees ABDC and closes at about 45 degrees ATDC. Reckon what are these numbers with the reed engines .... and do you reckon the timing probably changes with RPM? I suppose these numbers could be confirmed if you built a clear see-through tank and reed housing, and with the aid of ulta high speed photo strobe equipment in a lab, the actual time the reed closes and opens might be documented? I wonder is there at least any theory as to this reed timing? This might be one for you D. Dan?
I think the older Cox flapper type reed (á lá Space Bug) is a superior design and would maybe have a higher RPM limit because it is slightly spring loaded in closed positon, perhaps less apt to float out at higher RPMs?
See photo of experimental engine I made to test my "side" reed induction on the then proposed inline twin engine. I could not believe how WELL this set-up ran, even built another to make sure it was not a fluke .... amazingly the second one ran even better! This is a stock Pee Wee .020 reed housing with a Tee Dee .010 NV / venturi assembly, the whole assembly was simply glued (JB Weld) into the .049 Babe Bee's c'case for a quick test. This engine runs every bit as good, if not better, as does a stock .049 berryllium-copper rear read intake. The engine's tank in this photo is just that, a tank only .... the front reed housing has been sealed off with JB Weld epoxy ..... this is the same reed / NVA / Venturi set-up as used on my inline Twin.
That you very much. I will be doing a website on the complete construction of this engine in the not too distant future. To give you a few clues now, most of the parts are stock Cox parts .... the front case and c'shaft are from a Cox Car reed valve engine, used only beause the c'shaft is somewhat stronger. See post #41 for carb intake detail. Very few parts need be fabricated in order to build this engine. The tricky part is, as you know, getting the front and rear shafts mated ..... I will show you one photo with front carb intake removed ..... this photo tells a lot. The cranks are very cleverly mated by increasing the length of the front shaft's crank pin .... not by adding material, but by removing material from the original shaft. The hardest part of making this engine is modifying the front shaft and making the shaft coupling disc. The rear shaft is a totally stock regular reed Black Widow type and the coupling disc fits on to the rear shaft much the same as does a stock drive washer. See photo of the crank mating set-up. This photo shows the front cylinder's rod lower-end looking right at you, to it's left is the front crankshaft web, to it's right is the power coupling disc, this disc was fabricated from a "basta_d-file" .... and yes, it was a bast_rd to fabricate using basically only a Dremel tool!
My next twin will use Tee Dee shaft for front c'shaft and Killer Bee shaft in rear, this for more strength. Also I will be supporting the rear shaft at the power disc with a single ball bearing on next effort. Presently this engine is set-up for only mild running .... it will turn a Cox 7-3.5 prop at 15,500 RPM on low nitro and the old #302-1 hemi-heads. I am afraid to push it any faster because of the limited strength of the present stock reed type c'shafts. The sound is something to behold ..... I can send you a sound clip of the engine actually running if you like?
Can you .zip the .wav file? If so, it can be attached to a post on this forum. If not please email it to me direct. I haven't smoked in almost 20 years but I'm sure after hearing it run, I'll have to go change my skivvies and lie down for for a post-orgasmic cigarette!
Could you find the time to post a thread about your unique Cox engines over on the RCU 1/2A forum? Those guys'd eat this stuff up! http://www.rcuniverse.com/forum/%26quot%3B1%2F2_A%26quot%3B_%26amp%3B_%26quot%3B1%2F8_A%26quot%3B_planes_%26amp%3B_aircraft/forumid_70/tt.htm
"He who dies with the most good Cox engines wins!"