blw

My Feedback: (3)

That's a lot of money. It seems someone in the U.S. would be more than qualified to do the parts replacement.

j lauria

My 9-99 has had about 3 gallons of fuel run thru it. A good bit of that during break in. I am considering taking the engine apart myself and trying to replace the rings and bearings. A friend suggested flooding the engine with oil and turning it over vigorously with an electric starter to see if the rings might free themselves up. I think that this would have to be done with the glow plugs removed. I will at least remove the back plate and inspect the inside. If anything interesting shows I shall photograph it and post pictures.

Maxam

My Feedback: (62)

I would definitely check the US Mail!

blw

My Feedback: (3)

Glow fuel is excellent for freeing up parts, especially engine parts with old castor build up. I leave the glow plugs in and try to fill all of the inside with glow fuel. I have some cork to plug the carb intake. I usually fill from the backplate just so I can see inside and it's easier to flush out the next day.

Pretendpilot

i am trying to solve a leaky head-cylinder joint...have removed the head/cylinder assembly from the engine, BUT...
.
the head is very tight on the cylinder - i cannot easily get it loose with my early, careful attempts. is there a tool/set that is good for this? do i need to torch the head (is it locktited)?
.
anyone that has done this have any tips?

j lauria

Tom,
I have been told that UPS and DHL maintain control of a package all the way to its destination. US Mail does not maintain control of a package once it reaches the destination country and it becomes the responsibility of the local mail delivery system. It makes me a bit nervous to trust a valuable item to a system which may or may not be responsive to long distance inquires about lost items. DHL delivery to India $640.

I wish that Pete Bergstrom was still with Horizon . He was very responsive to my questions about UMS engines and encouraged me to buy the 9-99 for my 87 inch Stearman.

John

Maxam

My Feedback: (62)

Yes, It seems things went sour after he left. Is Horizon that unresponsive? If so I may have to back out of this thread. I will not associate with poor service. -Tom

j lauria

Tom,
Don't be too hasty. Yesterday I contacted Horizon. Thru a third party, who had returned my call, I was able to communicate with the service tech who takes care of repairing radials. The service tech, to whom one may not talk directly, assured the person I was talking to that he could repair the engine without sending it to India. I am sending the engine to Horizon today.
The information you have provided, based on your experience, has been invaluable to those of us who are interested in these engines. The interest in these engines continues. Without your input, I believe that many modelers would not be able to live with one. My experience was indeed unfortunate but quite likely due to my failure to clear the engine of unburned fuel after failure to start.
Please do not close the thread. Modelers out there are counting on you for advice. My experience with Horizon reflects my impatience with other product support persons who do not seem to be very responsive until pushed.
John

j lauria

To all who have been following this thread; regarding shipping costs.

To send a UMS 9-99 to India via UPS from East Aurora ,NY 14052 I was quoted $625. DHL $640
To send the same via US Postal service I was quoted $95. For a bit more it can be sent by registered mail and insured for full value.
To send the same to Horizon in Champaign Il I paid $22.50 for priority mail service and $500 insurance.

As you can see I made the decision to send it to Horizon. I will keep you posted about my repair experience.

John

Maxam

My Feedback: (62)

OK John, I am very glad to hear you finally got someone who has initiative. Let us know when you get your engine back! -Tom

Linkan2

Hello
now I got home a carburetor on min7-35.
bought a carburetor to Saito FA90r3.
My son helped turn a bush in brass.
I will come back after the test run, they will be exciting.
I want to believe that they are better quality Saito carburetor ..

Maxam

My Feedback: (62)

Hey Lars, I think you are in for a pleasant surprise! Do not over lean the idle or it will cut off the higher throttle settings. -Tom

Linkan2

thanks for the info Tom.
I'll think about the, we'll see how they go.
They'll just stop raining here so I adjust the engine
Lars

Maxam

My Feedback: (62)

Hey everyone, I just got back from the field flying my 50cc size Yak 55SP. It has the 7-77 with the OS Pegasus carb. I have done some testing and I have found more satisfaction with the performance of this plane with a 25x12 laminated Xoar prop. I had to use the shaft extension because the airplane used to have a Saito 325R5. This prop loads the engine to 4400 rpm on the ground and unloads well in the air. The plane is ridiculously light at 15 pounds so the performance is nuts! Take offs are at 1/2 throttle and full throttle is rarely used. The engine runs much better and more consistent with this prop. The 7-77 is disproportionately more powerful than the older 7-70 and waayy more powerful than the Saito! -Tom

Linkan2

Hi
Today test, I flew Stearman with new carburetor.
Just a word, amazing ..... what a difference.
worked very well in the engine, successfully.
Sorry I forgot tachometer home on the bench, the return of the.

Maxam

My Feedback: (62)

Now your engine can actually be tuned rich enough at full throttle! I bet the power increased, cooler engine and will now last longer. -Tom

Linkan2

yes they were more power with the carburetor.
Could today start at a little more than half throttle
I also believe that Saito carburetor settings are better

Pretendpilot

just what kind of temps is it supposed to operate at?

Maxam

My Feedback: (62)

That is dependent on ambient temp. A properly tuned engine will always run cooler than too lean. As is any engine tune to max rpm's then back off the needle to slightly richer. The carb on the 7-35 cannot move the fuel properly so the engine is always too lean at full throttle even when the needle valve is unscrewed many turns.

Maxam

My Feedback: (62)

Lars, you got me motivated! Yesterday was a rainy day so I finally got around to installing the OS carb on my old 9-90. Like before I made an adapter and turned down the carb body so the carb does not get close to the firewall. I will tune it in today! Last winter I bought three of these OS carbs and now i have one engine to go. I appreciate your contributions to the thread. I am pleased this thread has great posters. We even get Pratt and Whitney ads!! I wish they would start producing radials again. -Tom

Maxam

My Feedback: (62)

Tom here again, test running the 9-90 on the OS Pegasus carb. Why i did not do that sooner??? Runs sooo much better and a nice low idle all day long and no cylinder dropping without glow assist! Now on to the old 7-70 in the corsair......

Linkan2

Hi Tom
it was funny to hear that I can spread motivation.
what you write about your 9-90 I have also noticed.
going out in the morning so I will return for more info.

On Saturday I will go on air show.
Swedish Air Force celebrates 90 years so let's see very old & new planes in the air.

Pretendpilot

chorner, check you pm's.

Linkan2

https://www.youtube.com/watch?v=C9ndgUXouvU test flight with UMS 7-35 radial engine.
with a new carburetor from Saito FA120r3.
It works very well

Maxam

My Feedback: (62)

Lars, it seems you have made that engine perform well. Would you believe I had two 7-35's and they "ate themselves" . When new they had good compression but after a few runs the compression was gone in most cylinders. The carbs was so bad the engines could not be richened at full throttle! When the oil was drained out of the timing chest it was as black as can be so the cam followers were wearing badly. The oil should be crystal clear. Also the engine could be more than a half inch smaller diameter if UMS would use sensible rockers rather than those ones that stick out so far. -Tom