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UMS Gas Radial Engine Enthusiasts Rabbit Hole

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UMS Gas Radial Engine Enthusiasts Rabbit Hole

Old 04-18-2022, 03:52 PM
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Hyjinx
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Default UMS Gas Radial Engine Enthusiasts Rabbit Hole

Here goes Tom. Thanks for helping me start the new thread.
Aaron (Hyjinx)
My new UMS 125 from CH ignitions in Florida USA.

Brand new UMS 125 in a new to me Waco 60 Arf. Un started as of yet 4/18/22.
Thanks to anyone who is interested in sharing info on the current design UMS Gas Radials....


​​​​​

Last edited by Hyjinx; 04-18-2022 at 04:52 PM. Reason: Prono
Old 04-18-2022, 05:23 PM
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Maxam
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Default Well done Aaron!

I hope this thread comes alive.
The UMS 5-100; I now have 15 8 oz tanks of 40;1 redline ethanol free gas/ oil with 2 oz of Sea foam/ gallon. Nearly perfect carburation through the entire range from 600 rpm to 4500 turning a Xoar 25x12 prop. True horsepower is 4.65. Think of a DA50 with belt reduction. A Moki 215 is 9.5 Hp at 4000 rpm...This engine is very easy to start. The mid throttle is slightly lean but a lightly rich setting at idle takes care of that. No blubber rich areas through the throttle range. All cylinders run evenly!!! My UMS 5-55 and 5-100 do run rather hot at 230 F. The APS power fuel fuel pump is required (5-100).

Last edited by Maxam; 04-18-2022 at 05:25 PM. Reason: Omission.
Old 04-18-2022, 05:52 PM
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I am running a UMS 5-100 on a 1/5th scale Ziroli AT-6 Texan although I haven't done the maiden yet. Long story about that but the maiden probably won't happen till the end of the year. As Tom has stated, the 5-100 is an easy to start, smooth running engine. I am turning a semi-scale Biela 25x14, turning 4400rpm's.





Old 04-18-2022, 05:55 PM
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Seems RCU requires a member to have 10 posts before pictures/URL's can be uploaded, so let's see how this goes. This should be post #10 for me.


Old 04-18-2022, 05:57 PM
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Picture of the Ziroli AT-6 with a UMS 100-5 up front.

Ziroli 1/5 scale AT-6 Texan.
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Old 04-18-2022, 07:45 PM
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Originally Posted by Maxam View Post
I hope this thread comes alive.
The UMS 5-100; I now have 15 8 oz tanks of 40;1 redline ethanol free gas/ oil with 2 oz of Sea foam/ gallon. Nearly perfect carburation through the entire range from 600 rpm to 4500 turning a Xoar 25x12 prop. True horsepower is 4.65. Think of a DA50 with belt reduction. A Moki 215 is 9.5 Hp at 4000 rpm...This engine is very easy to start. The mid throttle is slightly lean but a lightly rich setting at idle takes care of that. No blubber rich areas through the throttle range. All cylinders run evenly!!! My UMS 5-55 and 5-100 do run rather hot at 230 F. The APS power fuel fuel pump is required (5-100).
Super cool Tom. Really looking forward to this flying season. I too have a Moki, yet un-started new 250 -7. Dr G recommended Amsoil Dominator for it. I have it so I think I will start out with it in the new UMS. Adrian recommended a APS for the 125. I bought in. I am using Spectrum equipment now from Frsky. Checking into sensor options.
Old 04-18-2022, 07:47 PM
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Originally Posted by okcrcpilot View Post
Picture of the Ziroli AT-6 with a UMS 100-5 up front.

Ziroli 1/5 scale AT-6 Texan.
That makes my knees shake! Absolutely beautiful Sir!
Old 04-18-2022, 07:48 PM
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Originally Posted by okcrcpilot View Post
Seems RCU requires a member to have 10 posts before pictures/URL's can be uploaded, so let's see how this goes. This should be post #10 for me.
Uploading pictures and video has been harder than landing the Texan for me lol.
Old 04-19-2022, 03:59 AM
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Hi Tom,
Did you have to use an adapter to mount the Saito carb on your 5-55.
Old 04-19-2022, 04:05 AM
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Here is a picture of the business end on my 1/3 scale BUSA PT-17. UMS 260-7, that has performed flawlessly for 30+ flights now.

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Old 04-19-2022, 04:18 AM
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Originally Posted by okcrcpilot View Post
Here is a picture of the business end on my 1/3 scale BUSA PT-17. UMS 260-7, that has performed flawlessly for 30+ flights now.
Do you watch temperature on cowled and open air set ups? Seeing both, I wonder if the Texan rums hotter? Assuming the same oil mix and octane rating and non ethanol gas blends....
Old 04-19-2022, 04:40 AM
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I no longer monitor head temps on the 260 since I have a lot of flights on her. Since I fly Spektrum I am using their temperature sensor to keep an eye on the 100 in the AT-6. Not having flown the plane yet, I don't know what the readings will be although on the test stand average was 170°

EDIT: Depending on the head temps of the 100-5, I may have to construct some sort of engine baffle. This would be a new undertaking for me so any and all suggestions/recommendations will be appreciated. Also, I used Amsoil Dominator in my radials at a 50:1 ratio and so far have not encountered any problems. I lube everything on the first flight of the day with gear lube.

Last edited by okcrcpilot; 04-19-2022 at 05:35 AM. Reason: Update
Old 04-19-2022, 04:43 AM
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GI Jon, yes I did. I hope the O-rings last with gasoline. Neat little engine. (5-55)
One other thing I like about the 5-100, still uses the little glow size spark plugs. I talked to Adrian about the thick R-Excel spark wires that are cumbersome especially on the smaller engines. He said the thinner wires do not work well with a hot spark.
To anyone interested. I have completed my Schlundt 46% Bowers Fly Baby using a Moki 257.
Nice Texan and Stearman and Waco!

-Tom
PS Great title for the thread!

Last edited by Maxam; 04-19-2022 at 04:45 AM. Reason: Omission.
Old 04-19-2022, 05:05 AM
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Originally Posted by Maxam View Post
GI Jon, yes I did. I hope the O-rings last with gasoline. Neat little engine. (5-55)
One other thing I like about the 5-100, still uses the little glow size spark plugs. I talked to Adrian about the thick R-Excel spark wires that are cumbersome especially on the smaller engines. He said the thinner wires do not work well with a hot spark.
To anyone interested. I have completed my Schlundt 46% Bowers Fly Baby using a Moki 257.
Nice Texan and Stearman and Waco!

-Tom
PS Great title for the thread!
Yeah Tom. I'll probably want to install the Saito carb as well.
Old 04-19-2022, 05:37 AM
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Originally Posted by Maxam View Post
GI Jon, yes I did. I hope the O-rings last with gasoline. Neat little engine. (5-55)
One other thing I like about the 5-100, still uses the little glow size spark plugs. I talked to Adrian about the thick R-Excel spark wires that are cumbersome especially on the smaller engines. He said the thinner wires do not work well with a hot spark.
To anyone interested. I have completed my Schlundt 46% Bowers Fly Baby using a Moki 257.
Nice Texan and Stearman and Waco!

-Tom
PS Great title for the thread!
Tom, By chance are there any pictures of the Fly Baby?? Just have to see the 257 on the front end of that Baby!!

Gary
Old 04-19-2022, 06:32 AM
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Originally Posted by Hyjinx View Post
That makes my knees shake! Absolutely beautiful Sir!

YES! What a beauty.


Old 04-19-2022, 07:23 AM
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Default Fly Baby

About to install windshield.

Old 04-19-2022, 08:22 AM
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Originally Posted by okcrcpilot View Post
I no longer monitor head temps on the 260 since I have a lot of flights on her. Since I fly Spektrum I am using their temperature sensor to keep an eye on the 100 in the AT-6. Not having flown the plane yet, I don't know what the readings will be although on the test stand average was 170°

EDIT: Depending on the head temps of the 100-5, I may have to construct some sort of engine baffle. This would be a new undertaking for me so any and all suggestions/recommendations will be appreciated. Also, I used Amsoil Dominator in my radials at a 50:1 ratio and so far have not encountered any problems. I lube everything on the first flight of the day with gear lube.
Thanks. Good help. I am going to construct the baffle of a 12x12 aluminum flashing blank from the home dope show. Aka Home Depot lol. I'll photo doc and post.
Old 04-19-2022, 08:26 AM
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Place your 5-100 on a sheet of paper with a flashlight shining straight down. The shadow will be your template. Place the flashlight as high as possible so the image has the least enlargement. -Tom
Old 04-19-2022, 10:37 AM
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Thanks for the suggestion Tom. I wish I would have asked this question before mounting the engine on the plane!!! Oh well, it'll give me something to do the next time it rains!!! Thanks for posting pictures of your "Baby". I'll best she flys like a dream.
Old 04-19-2022, 05:27 PM
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Default UMS Radials…

I’m on my second UMS made radial, this one the 5-150 going on the TopRCModel P-47 96”. Plan on flying a SEP 23X14X4.





My UMS engine is the Tomahawk branded “Blackstar” 5-250 which I picked up bundled with a 1/3 scale Tomahawk Wilga. My experience with this engine along with Adrain’s support shifted me to this brand.





I run them both, as well as my (2) Moki 250’s & (1) Moki 215 on the APS fuel pump. They run strong, sound great and with the exception of the pump, require no changes out of the box. My Moki’s required switching ignitions, disconnecting the fuel pulse pump and don’t support RPM telemetry.

Cheers
Old 04-19-2022, 05:31 PM
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Default UMS manufactured “Black Star” 5-250 video

Here’s a video of the 5-250


Cheers
Old 04-20-2022, 04:51 AM
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GREAT looking planes, Mark, and thanks for posting a video of your Wilga. Do you still have your Stearman??

Gary
Old 04-20-2022, 10:07 AM
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Originally Posted by okcrcpilot View Post
GREAT looking planes, Mark, and thanks for posting a video of your Wilga. Do you still have your Stearman??

Gary
Thanks Gary, and yes still have the big Stearman w/Moki S215. Still have yours? Have you picked up a UMS radial???

Cheers
Old 04-20-2022, 10:28 AM
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Originally Posted by marksp View Post
I’m on my second UMS made radial, this one the 5-150 going on the TopRCModel P-47 96”. Plan on flying a SEP 23X14X4.





My UMS engine is the Tomahawk branded “Blackstar” 5-250 which I picked up bundled with a 1/3 scale Tomahawk Wilga. My experience with this engine along with Adrain’s support shifted me to this brand.





I run them both, as well as my (2) Moki 250’s & (1) Moki 215 on the APS fuel pump. They run strong, sound great and with the exception of the pump, require no changes out of the box. My Moki’s required switching ignitions, disconnecting the fuel pulse pump and don’t support RPM telemetry.

Cheers
Hey MarkspThe Tomahawk is the next purchase for me. I haven't been able to come up with a 180 Moki which was (is) my hope. I have one more airframe to finish out my Big Four.
Looking at a non Chinese Arf of a Bucker Jugenmeister single seat. The cz is Chinese unfortunately, so it's ruled out at this point. Please continue to post your experience with the UMS Tomahawk. Thanks Aaron-

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