UMS Gas Radial Engine Enthusiasts Rabbit Hole
#51

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Just recently installed the UMS 260 five cylinder in a Hangar 9 40% SU-26. Currently in the process of fine tuning the carb. This engine will eventually be installed in a Balsa USA 1/3 scale Stearman which may not be completed before the end of 2023. Looking forward to comparing the performance of this engine to my Moki 250.
#53


Wingspan of the BUSA 1/3 scale Stearman is 116" top wing, 112" bottom wing. Yes, 260 is a big engine. My PT-17 weighs in at 64lbs. wet but I have added a LOT of extras to it and I'm glad to have all that muscle up front.
#55


I don't have the five cylinder (mine's the 7) but I set the needles to what is recommended in the engine manual. I have never had to adjust them, even after having many flights on the engine.
Gary
#58

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Karolh, which size is your seven cylinder. I ask because on the 7 cylinder 50cc , comes with UMS carb, or you can get the Walbro carb. Is yours seven cylinder bigger with the Walbro carb, gasoline engine?
#59


My friend Dale Davis own a UMS 5 cylinder engine which is a beautiful piece of machinery with an awesome exhaust sound.
#61

Never done business with them, but I have heard from several people stories about slow deliveries. Probably the combination of Brexit and the current economy situation has affected their ability to deliver quite a bit. Probably not their fault because right up to Brexit taking effect they had a pretty good reputation for swift shipping. I don't know what is going on, but I know they used to be quicker.
#62

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Well, I can accept some of the slow reasons but it is going far enough for this kid. Two months is too long to order an item. I sent the money in British Lbs as he wanted. He has the loot. When he got the money transfer he ordered the UMS 7cyl. from India I would be thinkin. He has the engine acording the rare emails but has a problem with the ignition module. I say, fly the new module in. Test it and ship me the engine, simple. He is slow emailing me to inform me on the issues. Communication is bad.
#63

Well, I can accept some of the slow reasons but it is going far enough for this kid. Two months is too long to order an item. I sent the money in British Lbs as he wanted. He has the loot. When he got the money transfer he ordered the UMS 7cyl. from India I would be thinkin. He has the engine acording the rare emails but has a problem with the ignition module. I say, fly the new module in. Test it and ship me the engine, simple. He is slow emailing me to inform me on the issues. Communication is bad.
All I know is that he used to conduct his business in a proper way until about the time Brexit came into effect and I guess Covid and the war in Ukraine (or at least, the effect that has on global economy) did him in further.
Maybe things will get back to normal again, maybe they won't, fact remains that this is pretty much unacceptable. It is just sad to see, and I hope you get your stuff soon.
I have heard some guys reporting that a few angry mails did speed up the process, but no idea in how far that is true or just coincidence?
#65

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I guess it will rectify itself eventually. Thank you for the good wishes and Maxam, thanks, it is good to know some people get lucky that the 7-35 was in stock. Mine was back ordered and I understand it is in his location. Thank for the input guys...
#66

Aaron
#69

#70

Shoot Gary, Didn't know you were here too. I got myself locked out and into computer purgatory on RCU and haven't been able to log in for months!
Hope you guys are having a great summer.
So sorry to hear of the loss Tom. Devastating to lose one with so much time and money invested. Geeze it was beautiful in the pictures. Sad for that. Hopefully the Moki crank can get straightened ( or replaced) now that Carf has taken the Moki mantle.
I goofed up Gary! I have been up north most of the summer building staircases to the lake for my neighbors. Our club had a shindig Saturday last that i didn't plan to attend, but my cedar supplier crapped out on material i have been waiting on so i shot back down here and attended last minute. I should have called you, but it was literally last minute. I flew the Claude and ripped the OS FR 300 around on that 1/5 scale PT 17 a few hot laps but didnt have the Waco ready. Folks ALWAYS comment your late buddys work on that unusual mount, Just started the new 150 Friday afternoon so no chance of having it ready for Saturday. Been flying up north at Thompsonville and Frankfort with the club up there.
I was running the new 150 earlier and i ran the fuel pump dry and i think i smoked it! 250 dollar boo boo. Fitting myself for a dunce cap lol.
Barely made Wausean this year too. Drove home 5 hours to watch the races and got rained out at the Ohio line, they cancelled just as i got to the track HaHa. Did get to sit around an jaw with some of the old timer crew though, Good to see Slo Joe. Missing Mary Jane, AKA Dave Mutschall shared a tear for him with Joe. His widow has re-married. Sweet woman, super happy for her.
This Waco/150 thing is close sans the pump set back. Have almost a gallon of 32;1 through it. It is really impressive. Heading back north soon though, Found a guy near here to mill the cedar the other guy crapped out on. spost to be ready late tomorrow.
Does you club have any thing coming up soon? Maybe i could drag the new UMS cross town?
Love to see you and let you take Daves handiwork around the clouds at its old home field. Hope his widow is well this summer.
Looks like others here are happy with these "new" UMS designs too. Catching up on the forum after my layover in computer hell LMBO.
Cool seeing the thread is getting some use. Great bunch of people here..
Huzzah!
Your wordy ole pal...
Aaron-
Hope you guys are having a great summer.
So sorry to hear of the loss Tom. Devastating to lose one with so much time and money invested. Geeze it was beautiful in the pictures. Sad for that. Hopefully the Moki crank can get straightened ( or replaced) now that Carf has taken the Moki mantle.
I goofed up Gary! I have been up north most of the summer building staircases to the lake for my neighbors. Our club had a shindig Saturday last that i didn't plan to attend, but my cedar supplier crapped out on material i have been waiting on so i shot back down here and attended last minute. I should have called you, but it was literally last minute. I flew the Claude and ripped the OS FR 300 around on that 1/5 scale PT 17 a few hot laps but didnt have the Waco ready. Folks ALWAYS comment your late buddys work on that unusual mount, Just started the new 150 Friday afternoon so no chance of having it ready for Saturday. Been flying up north at Thompsonville and Frankfort with the club up there.
I was running the new 150 earlier and i ran the fuel pump dry and i think i smoked it! 250 dollar boo boo. Fitting myself for a dunce cap lol.
Barely made Wausean this year too. Drove home 5 hours to watch the races and got rained out at the Ohio line, they cancelled just as i got to the track HaHa. Did get to sit around an jaw with some of the old timer crew though, Good to see Slo Joe. Missing Mary Jane, AKA Dave Mutschall shared a tear for him with Joe. His widow has re-married. Sweet woman, super happy for her.
This Waco/150 thing is close sans the pump set back. Have almost a gallon of 32;1 through it. It is really impressive. Heading back north soon though, Found a guy near here to mill the cedar the other guy crapped out on. spost to be ready late tomorrow.
Does you club have any thing coming up soon? Maybe i could drag the new UMS cross town?
Love to see you and let you take Daves handiwork around the clouds at its old home field. Hope his widow is well this summer.
Looks like others here are happy with these "new" UMS designs too. Catching up on the forum after my layover in computer hell LMBO.
Cool seeing the thread is getting some use. Great bunch of people here..
Huzzah!
Your wordy ole pal...
Aaron-
#71

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Join Date: Feb 2008
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I have the UMS 7-90 and have almost a gallon of 32:1 through it now in the 4 minute increments that the book recommends. Almost ready to mount it in the airframe.
I was having quite a bit of trouble with getting it to top RPM. I even purchased the $250 German fuel pump that you guys are probably running and I am running that at full speed. After running my engine for about 3 or 4 minutes it does creep up to full RPM of 5250 on a 24x10, but its not consistent. I can come back down to idle and then the next time I ramp it up it only goes to 4800RPM. So I need to figure that out on the test stand before I put it in the airframe. I'm going to mount mine in the Phoenix Waco 60cc. I've been told I don't need to baffle the engine that it will be just fine in the cowl. I guess we will see. This isn't my first radial as I own a few of the Saito radials, but this is my first UMS.
I was having quite a bit of trouble with getting it to top RPM. I even purchased the $250 German fuel pump that you guys are probably running and I am running that at full speed. After running my engine for about 3 or 4 minutes it does creep up to full RPM of 5250 on a 24x10, but its not consistent. I can come back down to idle and then the next time I ramp it up it only goes to 4800RPM. So I need to figure that out on the test stand before I put it in the airframe. I'm going to mount mine in the Phoenix Waco 60cc. I've been told I don't need to baffle the engine that it will be just fine in the cowl. I guess we will see. This isn't my first radial as I own a few of the Saito radials, but this is my first UMS.
#72


I have the UMS 7-90 and have almost a gallon of 32:1 through it now in the 4 minute increments that the book recommends. Almost ready to mount it in the airframe.
I was having quite a bit of trouble with getting it to top RPM. I even purchased the $250 German fuel pump that you guys are probably running and I am running that at full speed. After running my engine for about 3 or 4 minutes it does creep up to full RPM of 5250 on a 24x10, but its not consistent. I can come back down to idle and then the next time I ramp it up it only goes to 4800RPM. So I need to figure that out on the test stand before I put it in the airframe. I'm going to mount mine in the Phoenix Waco 60cc. I've been told I don't need to baffle the engine that it will be just fine in the cowl. I guess we will see. This isn't my first radial as I own a few of the Saito radials, but this is my first UMS.
I was having quite a bit of trouble with getting it to top RPM. I even purchased the $250 German fuel pump that you guys are probably running and I am running that at full speed. After running my engine for about 3 or 4 minutes it does creep up to full RPM of 5250 on a 24x10, but its not consistent. I can come back down to idle and then the next time I ramp it up it only goes to 4800RPM. So I need to figure that out on the test stand before I put it in the airframe. I'm going to mount mine in the Phoenix Waco 60cc. I've been told I don't need to baffle the engine that it will be just fine in the cowl. I guess we will see. This isn't my first radial as I own a few of the Saito radials, but this is my first UMS.
When was the last time you pulled the plugs, especially #4 & #5, to see what they look like? A flying buddy had a similar problem and found those two plugs were fouled. Once he cleaned the plugs, all was well in radial land. This is a reason why most guys prefer 5-cylinder radials over the 7's. 5's don't foul the plugs as easily as the 7's do.
#73

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When was the last time you pulled the plugs, especially #4 & #5, to see what they look like? A flying buddy had a similar problem and found those two plugs were fouled. Once he cleaned the plugs, all was well in radial land. This is a reason why most guys prefer 5-cylinder radials over the 7's. 5's don't foul the plugs as easily as the 7's do.
I haven't pulled them all yet, so I did last night and cleaned them all up till they looked new. I'll give it a try today to see if those other cylinders fire up. I didn't know that about the 5 vs 7 cylinder great info.
#74

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J Tab
#75

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I was able to get my 7-90 to run to 5200RPM with the 24x10 Xoar prop. It even shot up to 5700 a couple times so I richened it back down a bit.
It seems to take quite a bit of warming up though in order to get it to run to 5200RPM. I let it idle for 2 minutes before going for higher RPMs and still it didn't start hitting higher RPMs till I was about 4 minutes into my run on the test stand.
Either way I have almost a gallon through it now so its time to install in the airframe and see how well it runs in the air!
It seems to take quite a bit of warming up though in order to get it to run to 5200RPM. I let it idle for 2 minutes before going for higher RPMs and still it didn't start hitting higher RPMs till I was about 4 minutes into my run on the test stand.
Either way I have almost a gallon through it now so its time to install in the airframe and see how well it runs in the air!