UMS Evolution Radial Care and Operation
 

Last April at the Toledo Show I was walking near the Horizon hobby area and spotted a bunch of radial engines that looked like my UMS Seidel engines. I said "hey I have all the glow versions of these engines". I met Pete Bergstrom who is overseeing the import and development of these engines! Great, now there will be a place where we can get parts and support in the US. These engines are said to be available in November and will be branded under the Evolution label. The displacements will be increased from 70 cc and 90 cc to 77 and 99 cc respectively.

My name is Tom Maxam and I have been modeling since around 12 years old. I am currently 52 so, wow around 40 years. I ran gas and electric boats including competition electric with Ed Hughey as a mentor. Within a year of starting RC airplanes I went totally for the 4 cycle engines. I am up to 43 of them including six radials! I have a Hangar 9 corsair with 400 flights on it powered with a Saito 90 R3. I also have a 50cc Yak 55SP powered with a Saito 325 R5. When the UMS Seidels came out I had to have one. The first one was the 7-70 which I bench ran extensively to learn how to tune it and understand the quirks. Later I acquired a 9-90 and finally the 7-35. I soon discovered these are not paperweights but reliable solid engines that can be flown heavily. I am also quite experienced with the Moki 150 and 215 cc radials and have learned how to make them run well.

The goal of this thread is to discuss all aspects of the care and operation of these engines to help others realize success. Topics will include fuel, Ignition, tuning, valve adjusting, cooling, prop selection, preventing hydraulic lock, fuel pressure tapping and after run oil and corrosion protection. Pete Bergstrom from Horizon has agreed to occasionally contribute to this thread.

I currently have the 7-70 in a 91 inch corsair. It weighs 20 pounds and flies magnificently. The 9-90 is in a restored Robin Hood 99. Both planes have over 50 flights. The engines are showing no wear.

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This is an interesting topic! I have one question regarding those engines, i have read that the 7-70 run fine without glow support, what is it with this engine that makes it so reliable without glow? I am wondering since i have a ASP 400 which runs terrible without glow support !

RE: UMS Evolution Radial Care and Operation
 

Nils, Good topic! The main reason I suspect is the much lower oil content. You are going from 16 to 18% oil way down to 6 to 8% oil. Also these engines are supplied with OS type F glow plugs which are the best. I do not run on-board glow in any of my engines. The other day I flew my 9-90 on my Robin Hood 99 7 times and never lost a cylinder!

RE: UMS Evolution Radial Care and Operation
 

<span id="result_box" lang="en"><span class="hps">Hi</span>
<span class="hps">I have a</span> <span class="hps">UMS</span> <span class="hps">Seidel</span> <span class="hps">7-35</span> <span class="hps">who have</span> <span class="hps">worked very well</span><span>,</span> <span class="hps">no</span> <span class="hps">problems</span> <span class="hps">in the air</span> <span class="hps">at all.</span>
<span class="hps">I</span> <span class="hps">have</span> <span class="hps">23</span> <span class="hps">flights</span> <span class="hps">passes</span> <span class="hps">and it has not</span> <span class="hps">been any problems</span> <span class="hps">yet.</span>
<span class="hps">But I'll</span> <span class="hps">probably</span> <span class="hps">buy</span> <span class="hps">a set of</span> <span class="hps">ring for</span> <span class="hps">the exhaust.</span>

<span class="hps">I am very pleased</span> <span class="hps">with the engine</span> <span class="hps">so</span> <span class="hps">far

Lars <br type="_moz"/></span></span>

RE: UMS Evolution Radial Care and Operation
 

Thanks for your post Lars. You might show pictures. I need to figure out how to post pictures myself!

I would like to discuss correct propellors for these Engines. When the 7-35 was released last year the top recommended rpm was a ridiculously slow 5200. The engine would be loaded down severely at that rpm and less than 1 hp would be developed! An APC 17x8 was turned at about 7000 and a Xoar 17x8 wood was about 6500. The Xoar has a larger hub size which matches the prop driver perfectly. The engine ran well at these speeds. The early carbs had to have a rich idle setting or else the mid to full range would be too lean regardless of high speed needle settings. The new carbs will address this. Notice these engines have an under square stroke to bore ratio along with minimal valve overlap. This translates into ideal loads at lower rpms. The 7-70 on my 91 inch corsair turns a 22x10 3 blade warbird Xoar prop at 4500 rpm. There is no detonation and the engine runs quite cool! As mentioned it flies this plane with authority. I take off at half throttle. A two blade prop should be around a 22x12. Some of you might say why the high pitch? This is not high pitch for this diameter. A diameter to pitch ratio should be around 2:1 or more for improved aerodynamic efficiency. Many people say I have a slow WW1 plane, well throttle back and it will fly well and the engine will sound more realistic. 3D is where low pitch props with great diameter work well due to the high thrust at near zero speed. Increase speed with these props and the aerodynamic efficiency drops dramatically. My 9-90 swings a 24x12 at around 5800 rpm and hauls the 24 pound Robin Hood strongly. The plane will fly at 1/4 throttle with added up trim very slowly and sound outrageously realistic! Cannot do that with low pitch. I do experiment with many props. My Saito 90 r3 and 325r5 have a very over square stroke to bore ratio. This translates into developing power at much higher rpms. The 90r3 can only turn a 13x7 with out overloading and loosing performance. The 325r5 is suffering with anything above a 20x10. That is the advantage of these engines from UMS. They can turn the larger props and be in their ideal operating range, look more scale and enjoy the efficiency gained from larger props spinning more slowly. Think about the P51 and corsair etc. (full size) They have gearboxes in front of the engine that drops rpm, increasing torque so they could turn those huge props with high pitch for increased performance.

Recall the newer engines have greater displacements so the props might have to be bigger and/or have even courser pitch than before.

-Tom

RE: UMS Evolution Radial Care and Operation
 

I noticed a number of people have viewed this thread. Do you guys and gals have a UMS Seidel already? What are your plans for these engines. Let us know about your projects! Dont have a radial yet? Let us know what you want to put one in. Do you have worries about owning one and being able to run it and take care of it. Speak up! Lets keep this fun.....Tom

Hey Pete lets get these guys fired up. How about putting that picture from the recent ad in Model aviation in here. Very sharp!

RE: UMS Evolution Radial Care and Operation
 

Tom,

Thanks for taking this on. I am attaching the photo you spoke of. Your mail must be faster than mine because I haven't seen the ad yethttp://www.rcuniverse.com/forum/js/f.../sad_smile.gif. I'll also add to this thread later with some build pictures from the Seagull 1.20 size AT-6 I mounted the EVO 735 radial in, complete with our new collector ring. Sounds great and certainly keeps a bunch of the mess of the airplane!

Pete

RE: UMS Evolution Radial Care and Operation
 

<span id="result_box" lang="en"><span class="hps">Hello</span> <span class="hps">all</span> <span class="hps">engines</span> <span class="hps">fans</span>
<span class="hps">I have flown</span> <span class="hps">my</span> <span class="hps">best</span> <span class="hps">7-35</span> <span class="hps">with</span> <span class="hps">18x8</span> <span class="hps">prop</span> <span class="hps">from</span> <span class="hps">menzs</span> <span class="hps">wood.</span>
<span class="hps">now</span> <span class="hps">from</span> <span class="hps">Graupner</span> <span class="hps">18x8</span> <span class="hps atn">"</span><span class="atn">G-</span><span>Sonic</span><span>"</span> <span class="hps">looks like</span> <span class="hps">APC</span><span>, but</span> <span class="hps">cheaper</span><span>, rpm</span> <span class="hps">6800th</span>
<span class="hps">My</span> <span class="hps">PT</span> <span class="hps">17</span> <span class="hps">Stearman</span> <span class="hps">weighs</span> <span class="hps">6.5 kg</span> <span class="hps">and there</span> <span class="hps">is</span> <span class="hps">no problem at all</span><span>,</span> <span class="hps">is power</span> <span class="hps">over</span><span>.</span>
<span class="hps">I</span><span>'ve tried the</span> <span class="hps">18x10</span> <span class="hps">but there</span> <span class="hps">was nothing</span> <span class="hps">good</span> <span class="hps">flying weather</span><span>, so I</span><span>'ll be back with</span> <span class="hps">the</span> <span class="hps">test</span>
<span class="hps">Lars</span></span>

RE: UMS Evolution Radial Care and Operation
 

Here's a picture of the AT-6 with EVO7-35 and collector ring. BTW - I've test flow APC 16 x8, 16 x 10, 17 x 8, 17 x 10, 17 x 12, 18 x18, and 18 x 10 on this airplane. The best combination of load, pitch speed and aircraft speed for this plane is the 17 x 10 prop. turns about 6,800 rpm and provides a nicely manageable realistic airplane speed with the climb power as what you would expect of an AT-6. Very realistic in flight and because of this I did very well at the Bob Evan's Fun Scale event in August with this combination.

Pete

RE: UMS Evolution Radial Care and Operation
 

All, Very embarrassing but how do you post pictures from another file on your computer? Thanks -Tom .................OK figured it out!

RE: UMS Evolution Radial Care and Operation
 

I think I figured it out! Here are photos of my corsair and Robin Hood 99. -Tom

RE: UMS Evolution Radial Care and Operation
 

<span id="result_box" lang="en"><span class="hps">ok</span> <span class="hps">can</span> <span class="hps">any of you</span> <span class="hps">help me</span> <span class="hps">to post</span> <span class="hps">pictures</span> <span class="hps">please</span>
<span class="hps">Lars</span>
<span class="hps">ps</span> <span class="hps">I</span> <span class="hps">have</span> <span class="hps">many pictures</span></span>

RE: UMS Evolution Radial Care and Operation
 

Your planes look awesome Tom, full of radial engine up front! :D

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Lars, Below the message box you will see upload files. Do that before typing. Click on the one that says image. You will then get a prompt to choose file and your photo's should come up and then select the ones you want. Hope it works! -Tom

RE: UMS Evolution Radial Care and Operation
 

Thanks Tom. They are fun to fly. I want to put the 7-35 in a Sig Waco SRE. -Tom

RE: UMS Evolution Radial Care and Operation
 

Enter the URL of the link?????
Lars

RE: UMS Evolution Radial Care and Operation
 

You have to hit "reply" first. Then the easiest way is to go to the "Click here to upload images and files!" link and a box will appear with 12 lines with a browse tab next to them. Click on the browse tab and your computer files will come up. Choose the correct image file you want and either double clik the file or select it and click open. That file location will be loaded to the images list. When you have added all the images you want hit OK at the bottom of the box. RCU will then upload those images from your computer. Sometimes this can take a while so be patient until you see a response screen. Occasionally it will tell you the total file to upload is too large so you'll have to start over again with either smaller picture files or fewer images per upload.</p>

I am far from a computer expert but I have been making this work for me just fine. Good luck and we look forward to seeing your pictures!</p>

Pete</p>

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RE: UMS Evolution Radial Care and Operation
 

Ha Ha yes fixit
Lars

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Beautiful airplane!

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RE: UMS Evolution Radial Care and Operation
 

Lars, Thank you for the great pictures. That engine looks to be just the right size for that plane. I bet that Stearman loves the near zero vibration. Pete thanks for your better directions helping Lars.

My topic for today has to do with corrosion prevention. I do like running my radials on 8% oil and 7% nitro. That is part of the reason I do not use one-board glow power. When I am finished for the day I will start the engine after the tank is drained and let it quit on its own. I will then start it again and it will run a bit and quit. I will do this until it will not fire. Now I know there is no residual fuel in the engine. Now I remove one of the top pushrods and the follower so I have a hole directly over the cam ring and the rear main bearing. Into that hole I squirt about 10 ml of air tool oil chased with 2 ml of Evolutions Blue-block. I put the follower and the pushrod back and turn the prop over 3 to 5 times. The engine several days later is still creamy smooth indicating no corrosion. A major discovery I found. DO NOT use exhaust back pressure. The exhaust has highly corrosive effects on the engine. The carbs on these engines have plenty of draw if the tank is at the correct height and close to the engine. -Tom

RE: UMS Evolution Radial Care and Operation
 

<span class="Apple-style-span" style="font-family: Arial, Helvetica, sans-serif; color: rgb(69, 69, 69); ">Dear Mr.Pete<div class="msg-body inner undoreset" id="yui_3_2_0_1_131685343257692" style="margin-top: 25px; margin-right: 24px; margin-bottom: 22px; margin-left: 29px; overflow-x: auto; overflow-y: hidden; ">
This is Prakash from UMS. Thankyou very much for coming down here and spending some time with us.

Another thanks for testing the Evolution 7-35 on Piper J3.Hope you enjoyed the flight like us.

Its unfortunate that we didnt fly the YAK54, due to glitch. When I analysed the cause later, it turned out to be the interference from Iphones ,you and Mr.Gopal was having. When I first range tested the Cub , you were away in discussion with Mr.Gopal. But for the YAK you were near. So its a lesson for us who are using 35 Mhz sets- to switch off mobile phones when flying.After that I tested all receivers without the glitch.

Mostly this weekend I may fly the YAK. I will send photos later.

Kindly reply[email protected]</div><div></div></span>

RE: UMS Evolution Radial Care and Operation
 

<span lang="en" id="result_box"><span class="hps">Hey</span> <span class="hps">Tom</span>
<span class="hps">There</span> <span class="hps">way</span> <span class="hps">to</span> <span class="hps">rust</span> <span class="hps">protection</span> <span class="hps">your</span> <span class="hps">engine</span> <span class="hps">is</span> <span class="hps">in</span> <span class="hps">prinsip</span> <span class="hps">same</span> <span class="hps">as I do.</span>
<span class="hps">I have</span> <span class="hps">6%</span> <span class="hps">oil</span> <span class="hps">0</span> <span class="hps">nitro</span> <span class="hps">got</span> <span class="hps">on board</span> <span class="hps">glow</span><span>.</span>
<span class="hps">Now it is</span> <span class="hps">autumn</span> <span class="hps">here</span> <span class="hps">and</span> <span class="hps">near</span> <span class="hps">the end</span> <span class="hps">of</span> <span class="hps">flygsesongen</span><span>.
Lars
</span></span>

RE: UMS Evolution Radial Care and Operation
 

Can these UMS radials be run well on regular 15/15 fuel? here in Norway it is impossible to buy pure methanol.. I have been considering a 7-70 but need to run it on regular 15/15 fuel.

RE: UMS Evolution Radial Care and Operation
 

Nils,yes actually. When I got my first 7-70 I did run it on 16% oil and 15 % nitro and frankly it ran great! Just produced an oily mess! The higher nitro compensated for the high oil so low reliable idle was possible. Lars,the problem with on board glow is the great weight of the large batteries required. many people are happy however. The first picture of your most recent post was great! -Tom

RE: UMS Evolution Radial Care and Operation
 

Sounds great!
I found a place where i can purchase pure methanol, but it is directly from the raffinery in a 200 litre barrel as lowest quantity... a little much. I would have had fuel for the rest of my life !
But if i bought a 770 it would be absolutely best to run it without nitro and 6% oil to avoid the oil mess.

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<span id="result_box" lang="en"><span class="hps">Tom</span>
<span class="hps">You</span> <span class="hps">say it</span> <span class="hps">huh</span> <span class="hps">little</span> <span class="hps">broblem</span> <span class="hps">with</span> <span class="hps">them</span> <span class="hps">first</span> <span class="hps">carburetors</span> <span class="hps">to</span> <span class="hps">7-35</span><span>.</span>
<span class="hps">should I</span> <span class="hps">replace</span> <span class="hps">or upgrade the</span> <span class="hps">carburetor</span> <span class="hps">with other parts</span><span>.</span>
<span class="hps">Lars</span></span>

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Lars, Sorry it took so long to reply. I was in Philadelphia hearing the Philharmonic Orchestra playing along with the worlds largest pipe organ! Exciting concert. The carb is decent. I have heard there might be changes. Until then enjoy the engine!

RE: UMS Evolution Radial Care and Operation
 

Todays discussion refers to the danger of hydraulic lock on these radials. Due to the design of radials oil can seep down and pool into the bottom cylinders. Because liquids are basically non-compressible, if the engine is not checked first, the use of an electric starter or a strong arm can damage a connecting rod to the flooded cylinder. When getting ready to start the engine for the first time for the day, slowly turn the prop by hand. If you encounter a point where the compression is felt to be much higher, STOP!!!!!!! Drain that cylinder by removing the glow plug thus allowing the oil (or fuel) to leave. Over priming can also cause this condition. Next topic will cover valve adjustment -Tom

RE: UMS Evolution Radial Care and Operation
 

Hi guys - I am starting the build of a Top Flite Giant Scale Corsair and am determined if possible to power it with a Radial! I'm currently looking at the 7-77 or even 9-99 UMS engines but diameter is an issue especaially with the 9-99.

With an estimated weight of around 30lb I am concerned that the 7-77 which may fit does not quite have the power.

I'm looking to acheive ascale flight envelope with a three or evenfour,if I can,blade prop.

I will be following this thread with interest and would appreciate your thoughts.

Dave

RE: UMS Evolution Radial Care and Operation
 

Dave, My corsair shown on this thread weighs 20 pounds 4 oz with a 91 inch span and it is powered with the older 7-70. The newer 7-77 should give 10% more power. Mine swings a Xoar 22x10 3 blade well. The plane flies fine at 1/2 throttle. Actually I usually take off at less than 3/4 throttle. Be mindfull always with weight while building. No glue glops, less epoxy more CA. Recall these engines have low vibration so the airframe does not have to withstand massive vibration from a single. -Tom

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<span lang="en" id="result_box"><span class="hps">How</span> <span class="hps">nice</span> <span class="hps">it looks</span> <span class="hps">in the</span> <span class="hps">UMS</span> <span class="hps">Seidel</span> <span class="hps">7-35</span><span>.</span>
<span class="hps">It has</span> <span class="hps">been run</span> <span class="hps">in</span> <span class="hps">6</span> <span class="hps">hours</span><span>.</span>
<span class="hps">Nice and clean</span> <span class="hps">and no</span> <span class="hps">rust</span> <span class="hps">at all.
Lars</span></span>

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Tom - thanks for your reply. I am very conscious of managing weight whilst building, particularly aft of the Cof G and even more so at the rear of the fuse. Being conscious of it and achieving it are two different things though and I appreciate your comment.

I note these engines have an oversquare cylinder so that helps torque and from your experience its seems that the 7-77 may just be a good choice after all! I'm not sure that 10% more displacement will deliver 10% more power but its got to help. Unless I've missed something of course!!

This won't be quick build but I'll keep the thread informed . . . . either way.

Dave

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Dave, Please feel free to post progression of the build particularly the engine installation. I highly recommend bench running of the engine so you can become very familiar with its operation. They do run very cool so any overheating would be due to an extreme lean condition. The Xoar warbird 22x10 3 blade prop is excellent! -Tom

Lars, Thankyou for posting those internal pictures! I like to see engines being well cared for. -Tom

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Todays discussion concerns proper valve adjustment. First in my 30 years of 4 cycle engine flying I have found with complete consistency that valve adjustment is NOT critical. I have numerous times purposefully misadjusted valves and could barley perceive differences. What IS important is adjustment must allow both intake and exhaust valves to close completely or running goes to hell and valves and their seats get damaged on the double. Do not get me wrong I have high expectations of running quality and smooth transition through the throttle range.
Radials excepting the Saitos have a cam ring with multiple lobes to operate the valves. The more lobes the slower the cam ring runs relative to the shaft speed. Take a quiz! A cam ring has 5 lobe pairs.....what is its speed relative to the crank shaft?

OK on to the process; Removing all the glow plugs makes timing much easier so rotation is easy and the pistons can be seen at top dead center. Now start with the top cylinder even though this does not make a difference(you can start with any cylinder). Turn the prop to the point where both rockers are just moving and then one full turn to top dead center. You can see the piston through the glow plug hole. Turn the prop to the pistons highest point. Both rockers should have play. Adjust for correct clearance. You are NOT finished with this adjustment!! Now rotate the prop two full turns clockwise to the exact same position. The rockers might have the same clearance or have greater or lesser clearance. If lesser, readjust to correct. If greater leave alone. Now rotate the prop clockwise two full turns to again the same position. Check the clearance yet again, If lesser readjust if greater leave alone. The point is to never have a valve with too little clearance. A bit more does not hurt. Repeat this process for the remaining cylinders. You see each adjustment position is on a different cam lobe pair. This sounds like horrible tedium but once you get through a couple of cylinders it will go much faster than you thought. I can do the 9-90 in about one half hour. Maybe one glass of wine will help (only one!).

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Collector:

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Answer; ten crank shaft rotations to one complete rotation of the cam ring.

RE: UMS Evolution Radial Care and Operation
 

<span id="result_box" lang="en"><span class="hps">I have tried</span> <span class="hps">to adjust the</span> <span class="hps">valves</span> <span class="hps">as</span> <span class="hps">you</span> <span class="hps">said</span><span>.</span>
<span class="hps">There</span> <span class="hps">vase a</span> <span class="hps">new experience</span> <span class="hps">that worked well</span> <span class="hps">thanks</span> <span class="hps">Tom</span> <span class="hps">for the tip</span><span>.</span>
<span class="hps">I</span> <span class="hps">had a beer</span> <span class="hps">instead of</span> <span class="hps">wine
Lars<br type="_moz"/></span></span>

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Lars, I am glad you found that the valve adjustment instruction was clear even through a language barrier?? Your english is quite good however.