UMS Gas Radial Engine Enthusiasts Rabbit Hole
#152
My Feedback: (569)
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?
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
#157
Ditto on the Stearman, Love it!
#158
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?
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?
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!
#159
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.
#161
My Feedback: (15)
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.
The following users liked this post:
NavyE6FE (04-27-2023)
#163
My Feedback: (8)
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
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
#165
Join Date: Jun 2018
Location: Malaysia
Posts: 69
Likes: 0
Received 0 Likes
on
0 Posts
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.
Another Option is the UMS 5-180. Which one do you guys thinks it's the best between them.
#166
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.
#167
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.
#168
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.
#169
My Feedback: (3)
Its a Stinson so its going to fly scale like and I’d 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.
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.
#170
Join Date: Nov 2004
Location: Nanaimo,
BC, CANADA
Posts: 83
Likes: 0
Received 0 Likes
on
0 Posts
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.
#171
My Feedback: (3)
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...
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...
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
#172
Join Date: Nov 2004
Location: Nanaimo,
BC, CANADA
Posts: 83
Likes: 0
Received 0 Likes
on
0 Posts
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...
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..
#173
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
#174
My Feedback: (3)
Ok
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? Don’t send it back to MMM.
Did you ever try going to 40:1 from 32:1 oil?
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? Don’t send it back to MMM.
Did you ever try going to 40:1 from 32:1 oil?
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..