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UMS Gas Radial Engine Enthusiasts Rabbit Hole

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UMS Gas Radial Engine Enthusiasts Rabbit Hole

Old 03-27-2023, 05:08 AM
  #151  
Maxam
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The cowl is tight on that stunning plane. Baffling the engine will be required.
Old 03-27-2023, 05:30 AM
  #152  
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Thanks for the quick input guys.....
1) As it stands now the Stearman would just require some new wiring and updated servos, as well as an engine 'go over' before it's ready to fly....all 'relatively' quick items to perform.
2) The airframe was built, balanced and flown with the 3W120.....I'd use my Xicoy digital CG balancer to check things out
3) As both responses have correctly indicated the UMS 260 would be a whole different animal...requiring front-end "reconfiguration", re-balancing and of course re-maidening

While I'd sure like to give the Stearman a more 'scale' sound from the radial, as well as a whole new level of power, perhaps it would be best to 'leave well enough alone' and get it back in the air sooner then later?




Last edited by Hinckley Bill; 03-27-2023 at 05:33 AM. Reason: Added 3W120 motor mount pics
Old 03-27-2023, 06:22 AM
  #153  
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Tom,

Good looking plane and I'm happy to hear the Moki has found a new home. When do you plan on doing a maiden?

Gary
Old 03-27-2023, 10:07 AM
  #154  
Maxam
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Well Gary, when the weather permits! Thank you and Karolh for the compliments! -Tom
Old 03-27-2023, 02:42 PM
  #155  
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That looks amazing!
Old 03-27-2023, 02:45 PM
  #156  
Jamese1153
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Beutiful!
Old 03-27-2023, 02:50 PM
  #157  
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Originally Posted by harriermate
Hi Lozza,
Thatís a great looking Stearman. Just about to order a UMS 7-90 for my Flair Stearman (nearing completion). I know the kit may be different from yours but can you recall whether you needed ballast weight to balance the weight of your engine at the front?

Ditto on the Stearman, Love it!
Old 03-28-2023, 06:34 PM
  #158  
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Originally Posted by Hinckley Bill
Thanks for the quick input guys.....
1) As it stands now the Stearman would just require some new wiring and updated servos, as well as an engine 'go over' before it's ready to fly....all 'relatively' quick items to perform.
2) The airframe was built, balanced and flown with the 3W120.....I'd use my Xicoy digital CG balancer to check things out
3) As both responses have correctly indicated the UMS 260 would be a whole different animal...requiring front-end "reconfiguration", re-balancing and of course re-maidening

While I'd sure like to give the Stearman a more 'scale' sound from the radial, as well as a whole new level of power, perhaps it would be best to 'leave well enough alone' and get it back in the air sooner then later?



Hello Bill.
I have a similar set up. I bought a fresh built BUSA Stearman that had a DA 150 twin on it that ran great and flew it well.
My intention was a mount for a new Moki 250-7. The builder had done the recommended kit reinforcement for the larger engines. Yours looks similar. Mean Joe at BUSA opined the Moki 250 was a good choice and the airframe ( reinforced firewall mount base). The appearance with a aluminum ring added on the OEM boot cowl appears very correct and satisfying.
Size weight and power of the 250 can be summed up in two words. Throttle management. Much of the radial draw is not only appearance but low rpm flying similar to full scale mounts. If your going to fully cowl it. Toms suggestion on baffling is wise. I did so on my UMS 125 five cylinder. My temps at the exhaust spigots are very low.
Aaron-PesGlad to see the thread is still active.
That Moki looks perfect in the cowl Tom. Hope to see (and hear) video once you start it in rotation!
Old 04-02-2023, 12:07 PM
  #159  
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Originally Posted by cymaz
Excellent choice a radial. Just watch that too much power can spoil a Model....it sounds like your more than doubling the engine size.
The engine size might double, but the power will be roughly the same if not actually lower: Radials do produce, for their displacement, relatively low outputs.
Old 04-27-2023, 08:51 AM
  #160  
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New from UMS.
https://umstech.in/?product=3-100cc
Old 04-27-2023, 10:40 AM
  #161  
David Jackson
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Currently running the UMS 260 on a Hangar Nine 40% SU-26. The engine idles at 900 rpm and 4750 rpm at full throttle spinning a Bambula 32x14 two-blade propeller. Still working to get the starting procedure down, but so far happy with the engine performance. This engine will be installed on a BUSA 1/3 scale Stearman in the future.
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Old 04-28-2023, 08:35 AM
  #162  
Maxam
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Lars, looks like UMS wants to compete with Saito!
Old 04-30-2023, 10:18 AM
  #163  
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Installing a UMS-150 in a TopRC P-47. Does anyone know where I can get a spinner hub (scale, using 4b prop)? I know TruTurn went out of business.
Also, are you guys removing the spring tensioner off of the throttle body and the idle adjuster screw? I use to remove those on the DA and Moki engines.
Thanks!
Tim
Old 04-30-2023, 11:19 AM
  #164  
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Hey guys I have a line on a UMS 115 for a great deal. wondering if this is a common size? Are there many airframes that this would be used in? Thanks
Old 05-01-2023, 02:04 PM
  #165  
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Hi guys, I'm interested with UMS 7-160 for cy model LA7. Will be running with 3 blade 26x14-16pitch (Depend on RPM)
Another Option is the UMS 5-180. Which one do you guys thinks it's the best between them.

Old 05-12-2023, 11:45 AM
  #166  
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Originally Posted by partshunt
This UMS forum is what I have been looking for. I just bought a 50cc, 7cylinder ums on gasoline. Does anyone have experience with the 50cc? It is not supplied with the Walbro carb, it has the UMS carb. Cant wait to fire it up.I have two Mortons but they are apart, wont star, too low compression. This UMS 50cc -7cylinder good for what wingspan.?

I'm an old Alaska guy (81 years) and am considering purchasing that 50cc 7-cylinder radial from Adrian in order to put it into a Top Flite Stinson Reliant I am going to eventually build. Adrian wanted me to consider the 75cc 5-cylinder instead of this 50cc 7-cylinder but it's too large and won't fit inside the cowling. The main reason I'm commenting here is that I found a source over in the UK that makes an adapter for this engine in order to use a Walbro carb. Uh! Oh! I just discovered here that since I haven't posted very much here I am not allowed to post URLs yet. I wanted to give you that info but can't. I'm sure you can find this company by doing a Google search with the name. This company is called Morris Mini Motors and they also sell UMS engines and all kinds of other stuff at cheaper prices too. However, I want to stick with Adrian here in the US because of the excellent support he offers. I hope this is helpful.
Old 05-12-2023, 12:02 PM
  #167  
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Originally Posted by 1967brutus
The engine size might double, but the power will be roughly the same if not actually lower: Radials do produce, for their displacement, relatively low outputs.

I totally agree with what you are saying here about the power output of radials. I have an RCGF 40 cc twin gas engine and it puts out more HP than a 7-cylinder 50cc UMS radial engine. I am trying to decide which engine I should put into this Top Fllite Stinson Reliant I will eventually build. I will most likely try to use the UMS radial since it is much more realistic and I will accept the loss of some HP even though it is much more costly and I don't have any experience yet with radials at all.
Old 05-12-2023, 12:08 PM
  #168  
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Originally Posted by partshunt
Has anyone purchased a UMS Radial from Minnie Morris Engines in the UK? I have ordered one two months ago, and I am still waiting???

Hmmmm........... Very interesting. Did you EVER receive that engine? I just sent an email message to Morris Mini Motors asking about a Walbro carburetor conversion they offer for the UMS 50cc 7-cylinder radial. I probably won't hear anything back from them I bet.
Old 05-15-2023, 06:17 AM
  #169  
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Its a Stinson so its going to fly scale like and Iíd think the 50cc has plenty of power for scale flight. Buy the engine from CH Ignitions and if you notice the issues that you think are carb related then order the carb adapter from Morris in the UK. You could also price out buying the engine factory direct. UMS has them on their website.



Originally Posted by Gozonablat
I'm an old Alaska guy (81 years) and am considering purchasing that 50cc 7-cylinder radial from Adrian in order to put it into a Top Flite Stinson Reliant I am going to eventually build. Adrian wanted me to consider the 75cc 5-cylinder instead of this 50cc 7-cylinder but it's too large and won't fit inside the cowling. The main reason I'm commenting here is that I found a source over in the UK that makes an adapter for this engine in order to use a Walbro carb. Uh! Oh! I just discovered here that since I haven't posted very much here I am not allowed to post URLs yet. I wanted to give you that info but can't. I'm sure you can find this company by doing a Google search with the name. This company is called Morris Mini Motors and they also sell UMS engines and all kinds of other stuff at cheaper prices too. However, I want to stick with Adrian here in the US because of the excellent support he offers. I hope this is helpful.
Old 05-15-2023, 04:07 PM
  #170  
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Originally Posted by Gozonablat
I'm an old Alaska guy (81 years) and am considering purchasing that 50cc 7-cylinder radial from Adrian in order to put it into a Top Flite Stinson Reliant I am going to eventually build. Adrian wanted me to consider the 75cc 5-cylinder instead of this 50cc 7-cylinder but it's too large and won't fit inside the cowling. The main reason I'm commenting here is that I found a source over in the UK that makes an adapter for this engine in order to use a Walbro carb. Uh! Oh! I just discovered here that since I haven't posted very much here I am not allowed to post URLs yet. I wanted to give you that info but can't. I'm sure you can find this company by doing a Google search with the name. This company is called Morris Mini Motors and they also sell UMS engines and all kinds of other stuff at cheaper prices too. However, I want to stick with Adrian here in the US because of the excellent support he offers. I hope this is helpful.
I purchased the 50cc 7cylinder from Morris with a UMS carb on it. Run fine but I changed to Walbro carb ordered with the engine. Had grief with the pump, sucking air, sent the Walbro kit back and am running with the UMS carb. Max RPM tho is 4700, not the 5700 RPM like on the factory dyno sheet....Joe
Old 05-16-2023, 04:40 AM
  #171  
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Hey Joe, I have the UMS 7-90 and the entire time I was breaking it in I could never get it to go above 4200RPM. When I started leaning it out to tune it it still wouldn't come up above 4200. Then suddenly while running it on the ground for awhile it came alive and jumped to 5200+ RPM. Now my normal routine is to rev it up on the ground at higher RPM for 2 or 3 minutes until it comes alive and then I go fly. I think its because the bottom cylinders are flooded.

Have you used a temp gun to see if your bottom cylinders are firing? Maybe that is the cause of your low RPM. I was also told that switching to 40:1 oil from 32:1 should help the cylinders come alive faster...

Originally Posted by partshunt
I purchased the 50cc 7cylinder from Morris with a UMS carb on it. Run fine but I changed to Walbro carb ordered with the engine. Had grief with the pump, sucking air, sent the Walbro kit back and am running with the UMS carb. Max RPM tho is 4700, not the 5700 RPM like on the factory dyno sheet....Joe
Old 05-27-2023, 09:49 AM
  #172  
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Originally Posted by Timbers
Hey Joe, I have the UMS 7-90 and the entire time I was breaking it in I could never get it to go above 4200RPM. When I started leaning it out to tune it it still wouldn't come up above 4200. Then suddenly while running it on the ground for awhile it came alive and jumped to 5200+ RPM. Now my normal routine is to rev it up on the ground at higher RPM for 2 or 3 minutes until it comes alive and then I go fly. I think its because the bottom cylinders are flooded.

Have you used a temp gun to see if your bottom cylinders are firing? Maybe that is the cause of your low RPM. I was also told that switching to 40:1 oil from 32:1 should help the cylinders come alive faster...

Timbers, I ran the engine a couple times since I read your post . My 7-50 cc runs better after accelerating a few times. but really unsteady rpm. The temps on the cylinders vary but nothing indicates that the lower cylinder are cooler, in fact, the lower cylinders run hotter than any upper cylinders, but it changes now and then. Will play with it more,. The dyno sheet from the factory says they got it uo 5700 RPM, with a UMS carb but I cant get it near that. Glad your flying anyway.. We lost our field to the environmental mental complainers..
Old 05-27-2023, 10:57 AM
  #173  
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Originally Posted by partshunt
I purchased the 50cc 7cylinder from Morris with a UMS carb on it. Run fine but I changed to the Walbro carb ordered with the engine. Had grief with the pump, sucking air, sent the Walbro kit back, and am running with the UMS carb. Max RPM tho is 4700, not the 5700 RPM like on the factory dyno sheet....Joe
Hey!! Thanks for this information you have provided. I also read the reply from the other person who explained about the bottom cylinders not firing and causing the low RPMs. That's pretty interesting. I wonder what Adrian would have to say about this situation. I like the good news about the UMS carburetor. I may end up purchasing this engine with the UMS carb and see how it works out. Adrian (CHignitions) has this engine in stock with the UMS carb on it. I'm going to keep looking for posts in various forums to learn more about this engine's quirks before I decide to buy it though.
Old 05-27-2023, 12:05 PM
  #174  
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sorry you lost your field where are you located?

Since you have some downtime maybe ask Adrian at CH Ignitions what he would charge to take a look at it and see if he can get it to run up to full RPM on the bench at his shop? Donít send it back to MMM.

Did you ever try going to 40:1 from 32:1 oil?


Originally Posted by partshunt
Timbers, I ran the engine a couple times since I read your post . My 7-50 cc runs better after accelerating a few times. but really unsteady rpm. The temps on the cylinders vary but nothing indicates that the lower cylinder are cooler, in fact, the lower cylinders run hotter than any upper cylinders, but it changes now and then. Will play with it more,. The dyno sheet from the factory says they got it uo 5700 RPM, with a UMS carb but I cant get it near that. Glad your flying anyway.. We lost our field to the environmental mental complainers..
Old 07-09-2023, 06:59 AM
  #175  
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Hi guys, I have started my 1/5 Corsair build (fokkerc) and am planning on running the 5-150 engine. What props have you guys had good luck with?

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