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UMS Gas Radial Engine Enthusiasts Rabbit Hole

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UMS Gas Radial Engine Enthusiasts Rabbit Hole

Old 11-26-2023, 12:01 PM
  #201  
lozza1965
 
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Thank you for the quick reply, I have no idea why they are so bloody messy, mates fly other makes of radials and have very clean running engines, just wonder if the cylinders are not burning the oil off, not getting hot enough, all I know is its really screwing the painted solartex finish.
Old 11-26-2023, 12:44 PM
  #202  
Timbers
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Originally Posted by lozza1965
Thank you for the quick reply, I have no idea why they are so bloody messy, mates fly other makes of radials and have very clean running engines, just wonder if the cylinders are not burning the oil off, not getting hot enough, all I know is its really screwing the painted solartex finish.
Does yours take a few mins to come up to full RPM? Mine usually requires at least 3-4 minutes of revving it up on the ground before the bottom cylinders light. It makes a lot of black gunk during this phase for sure.

I seem to have the blank gunk issues on my Saito radials as well.
Old 11-26-2023, 02:00 PM
  #203  
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After about a minute or so I'm up to about 5400 iirc
Old 12-07-2023, 05:09 PM
  #204  
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I have a UMS-150 on a TopRC P-47. After break in (40:1) and running a Biela 23x14x4 prop using a APS pump, what RPM's should I look for at full throttle when tuning?
Old 12-08-2023, 04:08 AM
  #205  
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Next spring I will have my TopRc FW190 flying with the UMS 5/150. Be able to give feed back then on rpm. Meanwhile would like to know the performance you are obtaining. Thanks!
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Old 12-10-2023, 12:57 PM
  #206  
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Is anyone looking to buy a 150/5? I have a new one and Iím not going to use it because Iíve decided to build a CARF Corsair with a Valach 250 instead. This engine has been bench run only for three tanks and itís ready to go. I think itís a great engine as far as I can tell so far and it sounds very healthy. Let me know if interested





Old 12-10-2023, 01:02 PM
  #207  
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Originally Posted by rgoinbroke
Next spring I will have my TopRc FW190 flying with the UMS 5/150. Be able to give feed back then on rpm. Meanwhile would like to know the performance you are obtaining. Thanks!
Thatís the exact same build I was going to do! I picked up the VarioProp 3 blade 32i set up and three blade spinner for it. Then plans changed and Iím working on a CARF Corsair so Iím selling the TopRC FW and UMS engine now. I can use the prop hub on the Corsair and I plan to come back around to an FW later on.
Old 12-10-2023, 02:32 PM
  #208  
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Black crap. We have a 125 running redline and one running Amsoil Dominator. Both push black crap identical.

​​​Tub o towels takes it right off. Small price to pay for that radial realism lol. Ever even close to a full scale radial ? Even more black crap.....

Second UMS 125 at our field running great right out of the box......
Old 12-14-2023, 01:35 PM
  #209  
Chuck Yeager
 
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Dear UMS fans,

I have just purchased a UMS 150 for my PZL 104 Wilga project.
Do you run it with an electric pump setup in your planes or just regular out of the box?
I heard that they are quite tricky to tune without a pump.

Thank you in advance for your feedback.

Old 12-15-2023, 12:06 PM
  #210  
Hyjinx
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Default The new 125

Here is the second Phoenix Waco online at our club. Mine is the same but has an earlier light kit.
Sorry. Can't add link to video site won't allow upload..

Last edited by Hyjinx; 12-15-2023 at 12:10 PM. Reason: Add pix
Old 12-16-2023, 06:36 PM
  #211  
Maxam
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Originally Posted by Chuck Yeager
Dear UMS fans,

I have just purchased a UMS 150 for my PZL 104 Wilga project.
Do you run it with an electric pump setup in your planes or just regular out of the box?
I heard that they are quite tricky to tune without a pump.

Thank you in advance for your feedback.
Chuck, get the pump!
Old 12-17-2023, 03:14 AM
  #212  
Chuck Yeager
 
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Dear Maxam,

I have already purchased Hacker PowerFuel Rx V2 and I should get it within about 2 weeks.
Do you haver any reccomendations on the pump settings? The manual only says that the it shoud be set up within 30%-60% range depending on motor size.
Any ideas where UMS 150 should sit within this range?

Thank you for your time and support.


Old 12-18-2023, 09:20 PM
  #213  
marksp
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Originally Posted by Chuck Yeager
Dear UMS fans,

I have just purchased a UMS 150 for my PZL 104 Wilga project.
Curious which Wilga?
Old 12-19-2023, 03:17 AM
  #214  
Chuck Yeager
 
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Tomahawk Aviation 3.2 meter
Old 12-19-2023, 05:47 PM
  #215  
Maxam
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I am not familiar with that brand of pump. Start at 50% power and see if you get linear response as you SLOWLY accelerate from idle to full power. This is only after the engine is well broken in.
Old 12-20-2023, 07:51 AM
  #216  
Hyjinx
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Originally Posted by Chuck Yeager
Dear Maxam,

I have already purchased Hacker PowerFuel Rx V2 and I should get it within about 2 weeks.
Do you haver any reccomendations on the pump settings? The manual only says that the it shoud be set up within 30%-60% range depending on motor size.
Any ideas where UMS 150 should sit within this range?

Thank you for your time and support.

Hey Chuck.
This 125 is running a linear curved pump.
Mine runs the same with the same pump running at a constant 5 volts. Experience says the curve is not mandatory. The only reason anyone has given is pump longevity. The engine will run well at any pressure. The walbro meters the fuel. Not the supply. The excess is returned to the tank. Keeping it simple.

5 volts.
Old 12-20-2023, 07:56 AM
  #217  
Hyjinx
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[QUOTE=Hyjinx;12790390]

Hey Chuck.
This 125 is running a linear curved pump.
Mine runs the same with the same pump running at a constant 5 volts. Experience says the curve is not mandatory. The only reason anyone has given is pump longevity. The engine will run well at any pressure. The walbro meters the fuel. Not the supply. The excess is returned to the tank. Keeping it simple.




This one is mine running constant line pressure at 5volts.
Old 12-20-2023, 10:41 PM
  #218  
Chuck Yeager
 
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Thank you very much for your support
Old 12-21-2023, 05:57 AM
  #219  
Hyjinx
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Originally Posted by Chuck Yeager
Thank you very much for your support
Your welcome Chuck. I started this thread to try to discern the quality and engineering of the UMS redesign of the original Seidel radials (a few generations ago). A lot of helpful info has resulted. The redesign and metallurgy seen to be holding up well based on responses from owners. Welcome to the family!
Aaron-
Old 12-26-2023, 07:52 AM
  #220  
Carlo Vangompel
 
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[QUOTE=Hyjinx;12790391]
Originally Posted by Hyjinx
https://youtu.be/aHQjFBObloo?si=Lp2DPPGG7uNIcCzx

Hey Chuck.
This 125 is running a linear curved pump.
Mine runs the same with the same pump running at a constant 5 volts. Experience says the curve is not mandatory. The only reason anyone has given is pump longevity. The engine will run well at any pressure. The walbro meters the fuel. Not the supply. The excess is returned to the tank. Keeping it simple.



https://youtube.com/shorts/q_bM-6nen...j8pEtkTQK0Vatg

This one is mine running constant line pressure at 5volts.
Well, that motor runs fine.
I also mounted a PowerFuel RX V2 hacker on my UMS150, and tested it out today but seems that the motor runs even worse than before, finally it stops running.
When I switch of the pump, rpm increases. It runs horrible with the pump.
I tried on low and high speed using a switch, but there is no difference.
Any idea what could be wrong?

Carlo
Old 12-26-2023, 08:54 AM
  #221  
Maxam
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Carlo, when using the pump you must screw in the idle and high speed mixture adjustment screws otherwise you will be too rich. Usually about 1 and 1/4 turns out from all the way in. -Tom
Old 12-26-2023, 10:26 AM
  #222  
Carlo Vangompel
 
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Originally Posted by Maxam
Carlo, when using the pump you must screw in the idle and high speed mixture adjustment screws otherwise you will be too rich. Usually about 1 and 1/4 turns out from all the way in. -Tom
thanks, I will try it this week. I also noticed to use 5V. I Have 7.4V Liion batteries but will test with 5V
Old 12-27-2023, 01:28 PM
  #223  
Hyjinx
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Originally Posted by Carlo Vangompel
thanks, I will try it this week. I also noticed to use 5V. I Have 7.4V Liion batteries but will test with 5V
The pump speed is contingent on voltage between 5-9 volts. That's why I leave mine at 5. Slowest rpm that won't starve the electric brushless pump motor. Toms experience mimics mine on needle adjustments more or less. I returned mine yesterday to factory settings and it tuned easy and fast with a bit of adjustment on both needles toward lean .
To the group...
Both mine and my club mates 125s are both experiencing partially stuck exaust valves on cold start and between runs when up to temp. They are not consistent cylinder wise but it seems always and only on the exhausts. We are running different oils (redline and Amsoil). Wondering if the factory fit between the valve stem and guide is/are too tight. Or a carbon build up on the stem?
Anyone else chasing this bug?
Old 12-27-2023, 02:01 PM
  #224  
Maxam
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Default Are you using

Sea Foam, 2 oz/ gallon? This prevented stuck valves for good.
Old 12-31-2023, 03:52 PM
  #225  
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Originally Posted by Maxam
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
what an excellent suggestion!!

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