John...
I'm a bit confused by your question...are you looking for info. on the Gas version or Nitro version?
I have the original Seidel 7-70 ( Nitro %5 / % 6 Oil ) in a 1/4 / 80" Fleet biplane...I've never weighed it but in't in the 20 lb range.
I've had a few excellent flights on it with an OS carb.....plenty of power and cruising at 1/2 throttle.
Good luck with your Bulldog project.
Eric

Hi Eric,
Its the 115, 9 cylinder gas engine I am interested in. I have started a few hand drawn doodles of the general configuration of the Bulldog. I am surprised that the build looks to be really quite staightforward. Dressing up the engine with the very prominent fuel distribution pipes will be an interesting challenge, as will the natural polished metal of the front fuselage, but after that it could have been designed with the modeller in mind. There is a very colourful example in the RAF museum Hendon. I may base it on that aircraft of I may base it on Douglas Bader's aircraft.
John

These new UMS engines are selling well, however I have not seen too many modelers post flight videos yet. I myself have the 7cylinder 160cc engine broke in a bit on my test stand, however I have not had time to hang it on my 1/3 Stearman yet. I posted the video link of a modeler successfully flying a 5-180cc version on a giant scale yak. I did watch a flight in person of an evolution 9-115cc glo fuel version flying a kit built Stearman at a fun fly a few years ago. The new UMS versions are upgraded in many areas, and include a collector ring exhaust pre installed at the factory. There are several videos on YouTube of them running on purchasers test stands, and they run and sound beautiful. Not sure how much more convincing info you need. I suggest you get one, run it, put it in a plane and enjoy! Maybe you will beat us all into the sky with it. ( Make a video). Most of us have many projects going at once. I still have to get custom flying wires produced in Europe to complete my plane.

According to the specifications on the UMS 9-115 radial, in produces 27.5 lbs of thrust with a 24x10 2blade prop. More than enough power to hover a 17.5lb plane! Hope this helps.

Hi guys.....I am having trouble getting my 7-77 to idle without the battery connected...tried lots of things.....new/o.s. carburetor. ..ect
after lots of trying i have lost confidence in engine and will sell engine, 2 glow harnesses and original carburetor and individual exhaust
(Has ring muffler on now)......engine never flown....oiled daily to prevent rust.
runs strong with battery attached!?!?!?
Price 800.00

I have the 7-70 original Seidel engine with Microsens glo system from Austria.
This glo system measure every glo plug while running and supplies (or not supplies) current to a cold running plug.
So my system actually is always " on " to some degree...but runs and idles perfectly.
Just curious what fuel / oil / nitro ratio you are running...i'm sure you have it right but just curious.
Eric

Badangle, I might have your answer. Years ago I could not get the engine to idle. I was stumped. It turned out some of the bolts to the intake tubes were loose on both ends. The engine was sucking air severely leaning it out. -Tom

Tom, I will check that out...thanks for the input.
​​​​​I need some help though. ..
I recall u have played around with valve settings and found its not super critical.
I find setting valves to be a pain (on this engine) and was wondering how bad (loose) settings
Would manifest themselves. ..?

my fuel is 10% intro,,7.5% oil...

Valve gap, I use recommended or a trace more loose.
 

Make sure you clear those lower cylinders! Very loose will give a better idle! But will loose power and beat up on the valve train.

Hey Eric
I also have an old original german made 7-77.
i have been un sure to run it.
Do u actually run and fly your engine regularly?
Have you a source of available parts?
I would live to run mine but am concerned about needing parts if something goes wrong.

I have the original 5-40 seidel. Very well made and durable. The carb was terrible and the Saito R90-3 carb greatly improved things. I cannot see what parts would be needed.

I think the original Seidel is a 7-70...at least that's what it says on mine! They also made larger ones.
I was extremely careful breaking mine in, I bought it from a guy who had it for almost 20 yrs. and never ran it !
I did notice that the valve clearances were somewhat uneven...I would set a valve to specs. than rotate it a few times and saw that when fully opened on that cylinder again the valve would have a different clearance!..I suspect that the cam that activates the 7 cylinders pushrods is not 100% accurate possibly.
As mentioned, I used the Microsens Glo system from Austria which has worked flawlessly...it will turn itself off automatically when the glo temp. is sustained ....some batt. usage is happening during each flight.
I had about 10 gentle test runs to break the engine in to full power and only to actual flights before my wing tip caught a fence post and is out of action til I get it repaired.
But the engine ran really well and had great power, but the torque is what surprised me with a large 24x6 prop on a 1/4 size Fleet Biplane.
I was also worried about spare parts, but figured finding a good machinist would be the way to go if anything broke.
I do know that the Evolution is a copy of the Seidel ( they sold them the patents and plans) so maybe the parts are interchangeable also.....

Seidel made the original. Seidel made an agreement with UMS in India about production, but broke the agreement when they thought the UMS had poor quality. UMS continued to produce them and continue to do so to this day. Evolution bought so many engines from UMS so they got their name on it. UMS has gradually come up with several versions of both gas and glow engines.

UMS homepage Radial Engine

Thanks for that clarification !!...good knowledge...

So I guess to the earlier question.....are the Seidel and UMS nitro parts 100% interchangeable ??

No unfortunately.

Interesting. Now I really want to run it lol!
I know you have time on your five cylinder Tom.
This report in the 7-70 really makes me feel like I should probably try it regardless of parts availability. Those sound like they have been reliable for you guys.
I am just shuddering at the idea of hiring a machinest to recreate a rod or forge shop to make a piston or similar.
I e mailed the "new " Seidel website for info. The site did elude to possible repairs and parts for some of the "older" Seidel's.
Hoping something comes back.

The seidels are durable but use 10% oil, some nitro (5% or more) do not hydraulic the two lower cylinders and use tons of after run oil such as Marvels Air tool Oil, even a couple of drops in the individual cylinders.

As always Tom, thanks for your help here. I just can't decide to mount this motor or not.
I sure would like to fly it, I picked up two Stearman 1/5 scale test beds over the winter for my smaller radials. I have flown the Sirius FR 30O and the Saito five cylinder so far. What fun. They both had loads of power on these #15-18 pound auw biplanes.
I want to get all of them up this summer if possible.

If you do run it use some castor in the oil. Prevents galling of the cam tract. -Tom

Thanks Tom
I bought some Sig castor. Been adding to my full synthetic blends. I like castor. Super cool lubricant.

The latest UMS gas radial 5&7&9 cylinder engines released on the market last year are now sold under the UMS brand. They redesigned the pushrods to have a deeper capture to prevent throwing a rod as tolerances slightly change during break in. The cam followers are now heat treated to reduce wear. The cylinder heads are machined from a solid billet of aircraft grade aluminum. All engines are shipped with exhaust collector rings installed. The electronic ignition systems are high quality components and designed in collaboration with RcExcell and CH Ignitions.
These new engines are certainly a welcomed improvement over the previous models of several years ago. They range from 55cc through 260cc offering a wider range of options to fit many more model plane sizes. I own one and it runs beautifully!

Which one?

7cyl 160cc.

Good news...and also that they are committed to improving their product !