Cybertom

Mr. Robison,

I was looking at my last message reply and it was way to abrupt. I could have done a much better job of making my point. I have all the respect in the world for you. Please forgive me, after all you have forgoten more than I'll ever know!

Cybertom

See if you can get some performance specs from him. It's a BIG mystery!

William Robison

My Feedback: (3)

Tom:

Maybe I just have a thick head I mean hide, of course, but I didn't see nything abrupt in your earlier posts.

Numbers on the engines? Somewhere I have all the TP specs, but they are all the older series and have no application to the latest production. If I posted what I have on them it wouldn't be fair. Suffice it to say that the older TP engines, when used in an appropriate airplane, were excellent.

The old Burgess/Morton was the real dog of model radials, very few people managed to get a plane off the ground with one, the ones who did could just barely maintain level flight. Anything more was completely out of the question.

Bill.

chasrb

Tom, you're making me look even harder at the Robart 780 now... I would like the Siedel, but, geezzz can't they get it together?

As for a gas radial, I'd love it, it sounds scale and all that..but RCS is not going to build an engine that would fit our 1/4 scale Stearmans- I asked. The 215 is way too heavy and too much power. A 100 or 125cc would be perfect!

HarryJ

My Feedback: (98)

Tom,
There is a guy near you that makes gas engines, Ken Baker at D&B engines in Warren OH. He also makes ignition systems to replace the old magnito systems. I wonder if he has ever attempted to build a system for a 5 cyl or 7 cyl radial?

Harry

Cybertom

Good question. Looks like we are building resources for an attempt at our own GAS radial engine

Hypothetically:

If we were to make an engine, should it resemble a particular full scale engine or not. If we were to mimic a full scale look what engine should it be? I have never seen a working model of a Continental radial engnie. They have a very distinctive look because the pushrods are behind the cylinders:

HarryJ

My Feedback: (98)

Great idea! I would vote for the look of the Continental, perhaps a 5 cylinder version to start. All of the ignition system could go to the front wih an exhaust ring in the rear behind the pushrods and lower than the rocker boxes. This guy can build the exhaust system.
http://www.keleo-creations.com/

Harry

HarryJ

My Feedback: (98)

Here is a 1/4 scale 9 cylinder Gnome radial. They do run but I think they are mostly static display.

Harry

Frogman1195

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Hey guys. I have a seven cylinder TechnoPower. Kelvin at keleo-creations did a great job a fabing me an exhaust. "pitts type" I have been wondering about the relatively low power that these TP's make (1 HP). What plane would you recommend attaching it to? Would love a stearman kit or arf.

Dave

William Robison

My Feedback: (3)

Tom:

Not only the Continental R-670 Tom, all the Kinner radials had the cam ring behind the cylinders, and the Wright J-6 "Whirlwind" also was made with the cam behind the cylinders. See picture.

Dave:

What plane would suit depends on which series engine you have. Check the serial, it will have an "A" "B" or "C" in it.

Bill.

PS to Tom:
The J-6 was also heavily biased in rocker box finning to the exhaust side. The R-670 had a little bit but not nearly as much. Again, see the J-6 picture. wr.

William Robison

My Feedback: (3)

Tom:

Another with the push rod tubes in the rear was the small Siemens radial used on the Bucker Jungmeister.

Bill.

Frogman1195

My Feedback: (2)

Bill,

It is a series "B" engine.

Dave

William Robison

My Feedback: (3)

Dave:

7B? That makes yours a 2.00 engine, power about like a 120 single.

Weigh the engine without the exhaust ring - if it's right about 30-31 ounces it's the AAC version, no real worry about overheating. If it's heavier it has the steel sleeves with the aluminum muffs, don't idle it too long or sit on the ground with the engine running.

In either case it will still have the cast master rod, so keep the speed below 6000 rpm.

Tower and Hobby People, maybe Horizon as well, have Stearman and WACo biplanes in 120 size that should be fine with your engine.

A 16x6 prop should be about right.

Bill.

Frogman1195

My Feedback: (2)

Bill,

Thanks. Just what I was looking for. Plus lots of great info. Thanks again.

Dave

chasrb

GOOD NEWS!!! Radial Fans !!!

Here is a link to the NEW Seidel page. It is not very functional, but it is there!
[link]http://euroscaleusa.com/SEIDEL-Radials.html [/link]


you know I'll be getting mine soon...

Reg Hinnant

My Feedback: (9)

Hi guys,
Anyone remember Forest Edwards jewels?
5 cyl, 6HP 12.5" dia, 8.5 lb Spark ign, dri sump lub. 24" prop at 5500 rpm
over $4000 many years ago.

William Robison

My Feedback: (3)

IOf we go back into history we see the old Burgess/Morton M-5 radial. Originally a training aid for teaching aircraft mechanics it would run, so naturally many people tried to fly them. The power to weight ratio was so bad that very few ever got one off the ground. Gasoline fueled, it wasn't strong enough to run on alcohol.

Bill.

ElectRick

My Feedback: (2)

Another vote for a Continental-style design. It would be a natural for Stearmans (obviously) and any other Conti 225 powered airframe, and having the pushrods in back affords a bit more protection for them in case of a (gasp!) crash or noseover. I just like the much cleaner look of the Conti.

I wonder how difficult it would be to design an engine that was 'reversible', meaning making the crankshaft so you could bolt on a prop adapter from either side, and making the cylinders reversible on the crankcase to facilitate reversing the direction of crank rotation?

There may be some practical engineering or design reason this wouldn't work, but hey, it's an idea to make a single design more aesthetically appealing to a wider variety of applications.

I wish I owned a lathe and a foundry--and the skill to make one myself.

Rick

William Robison

My Feedback: (3)

[b]Rick:

A model sized radial could easily be made with the cam ring in the rear, but in practical manufacture it's much easier to put it in front. this allows a crank shaft of conventional single cylinder appearance, it does not require any support behind the plane of the cylinders. This also allows the use of a one piece master rod. Stronger.

Almost all full size radials have a device called a "Diffuser" behind the rear crank bearing. It looks like it would be a supercharger, but its purpose is to mix the fuel and air, prevent condensation of the fuel, with the result of one cylinder running lean and another running rich. A big eggbeater in effect, whipping the fuel/air into a nice meringue for the cylinders to feed on. The diffuser is normally run at a multiple of the crank speed so it will be effective at low engine speeds. With a single row radial it's just easier to have the cam rings in front and the diffuser in the back. There is still a drive through the diffuser for the accessories, the magnetos, generators, starter motor, fuel and hydraulic pumps, so forth.

On a two or four row radial we can't have the rear bank's valves operated from a front cam ring, so a two row engine could have the cams between the banks, but that would make the crank shaft longer, leading to harmonic vibration problems.

Attached pictures are a Pratt and Whitney R-1535.

First, as it arrived for overhaul. In this picture you don't see the push rod tubes, they have already been pulled. But the front bank does have a front cam ring. The rear bank cam ring is just behind the rear cylinders.

The second picture is the crankcase after the jugs were pulled. The small round holes near the bottom are the outlets from the diffuser fan.

Last picture is the completed engine installed in the airframe.

Bill.

EDIT>> The R-1535 was a 14 cylinder two row engine, used mainly on the Douglas SBD dive bomber. wr.

R Barnette

My Feedback: (2)

I build my own two cycle radials of various sizes, it is a lots cheaper, just takes a little time to make one.
Ralph
[email protected]

William Robison

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[b]Ralph:

Do you use complete engines and gear them together? Or do you make a complete crankcase, a master rod, and some sort of scavenge blower?

Post some pictures, please.

Bill.

chasrb

Okay, I got my Seidel ST710 in and here are the photos;

For the glow driver system I think I'll go with the Sonictronic 7, I called the guys aer PME and I'd have to buy 3 2-plug drivers and a single to use their system. However, their system is one where it senses the temp of the plug and heats only the plug that has cooled off. As far as I know there is no throttle control on that unit... any other ideas?

bluehrnt

I am building a 1/4 scale Waco from Proctor. I should have built the 1/3 scale but I chose this one at the time. I am having difficulty finding a radial engine to match. They have told me the 1/4 scale waco will be around 22-25 pounds. It calls for a lazer 240 glow engine but I would like to scale it out with a radial. Any advice? The RCS gas engine is great but would be to heavy I believe for this model. I was told by proctor the OS radial FR300 is to weak in the HP versus weight ratio. Thanks for anyones help. I feel naked without an engine. I am very interssted in the Seidel and their website says they cost 2148 in US conversion, but Nick Ziroli want $2900. Quite the margin...........you would think that you could buy it for the same price as on the seidel webpage. Thanks,

Henry of Wisconsin

[email protected]

William Robison

My Feedback: (3)

[b]bluehrnt:

You might consider the Magnum/ASP radial. It's the same weight as the OS engine and one third more power.

Bill.

Cybertom

It seems to me that the engine you have will work just fine. According to the numbers that OS publishes it can make up to 32lb of thrust. If it was only 1 to 1 or 25lbs that would still be a hell of a lot of thrust from a scale perspective! You just need that BIG 22x8 prop.