Man Keith thats outstanding! You must be doing a great job with throttle management. I'm a little heavy on the pedal. I have a 20 oz. tank and I get 14 minutes. Thanks for the responses. Mike

Hi Guys,
With 26 runs on the engine and the mid range problem (making me fly at full a little more than necessary) I'm getting 14 minutes...I can get 3 intermediate routines, but I've had the engine quit on taxi back....
Chris

***20 ounces***

Mike,

I have tested the Webra pipe. I would get 100 more rpm with it, but on the 1.45 with the standard carb, it seemed a bit peaky, with a jump on the pipe I didn't like. On the 1.60 it seemed to run fine, as the 1.60 has a lot lower exhaust timing. But I'm still running the ES pipe, even on the 1.60. To clarify, I'm running the 140L90 ES pipe. I tried the shorter version of this that ES makes, but the rpm's went down about 200.

BTW, I have only flown with 15% Magnum fuel through both my 1.45 and now the 1.60. Of course, I have been using the MC carb in the model. But during bench running it was evident that if running the standard ProMix carb, 25% fuel gave it a cleaner mid-range.

And just FYI, the 1.60 I'm running, on 15% Magnum, turns a 17-12 APC at 8,200 set for take off. If I peak it will turn 8,400. I have a 20 ounce tank in the model, and after a 15 minute flight there's about 4 ounces left. I have about 45 flights on it and it seems to be getting stronger.

It could be throttle management, or it could be that your pump is forcing more fuel through than is needed. I know that doesn't seem to make sense since if that were true you'd think it would be too rich, but it's a thought.

I do work the throttle a lot when flying so that may be the case.

BTW, I just returned from flying and noticed that on my first 18 minute flight I had only about 1/8 th of a tank left. This is a bit less that I'd originally indicated. On the final flight of 19 minutes I had about 1/5 th to 1/6 th left. The difference in the flights is that the last flight I was working several maneuvers over and over and not flying the entire sequence. Probably this set of maneuvers didn't require as much power.

Another variable can be how much wind your flying in.

The plane I have is an Aries. It's an awesome slow flying plane. It's just incredible how this thing floats through the air. With this plane it's probably easier to be conservative on the throttle.

Thanks for clairifying your position Tony. With that kind of fuel economy the extra cost of fuel isn't a factor when compairing the engines overall cost to operate vs say a YS DZ.
Keith I have seen a picture of your Aries before. It's a beautiful plane. I'm thinking of building one this winter. Mike

The fuel consumption would probably change with 25% nitro, but I'm not sure how much. Perhaps someone out there would know a formula to figure this out.

From my experience I see no need to use 25% nitro. In fact, during the winter months one of the guys I fly with steps down from 15% to 10% nitro on his OS 1.40.

Keith

Hey Tony,
Thanks for keeping us updated on the WEbra developments. I have 3 Bully 1.45s and 2 WEbra 1.45s. Does the 1.60 have a significant power adantage or is it just more user friendly. I also have a couple of OS 1.40s and the Webras seem to have better fuel economy, but I try to run my OS as rich as possible to extend the life of the rear bearing.
-Will B.

Hello everyone,
I have been following this thread with much interest on the MC carb. Can someone give me the correct part number for the MC carb that is the one to use with the Webra 145 AAR. I spoke with someone at Horizon Hobby but he did not sound to sure. They list two Web3710 12mm and Web3711 9mm. Thanks in advance
Scott

Scott,
I've been told it's the 3711. From Tony's comments it sounds like the way to solve a lot of midrange issues on the Webra. I'd double check that number with Horizon.

Mike

cd3217,

Have you run your engine this weekend? Just curious if you'd tried any of the adjustments we'd discussed. Specifically the pump adjustment.

Keith

I've enjoyed the read and info in this thread, but often wonder why people run oil as low as 14%. If the manufacturers notes suggest it fine, but I for one cant notice the difference in the lower oil in my flying, but also know that with 20% I'm looking after my engine as best I can

Hey Chris, one of the guys in thread mentioned the 16.5x12W for the engine on the Zen. That would be a good try on the plane and I might have one at home, I have run this prop before and it works well.

Hope cleaning the crap out of the pump was the solution, from your last flight Im convinced thats what the problem was. I dont know why the engine MFRs dont put a very high quality filter with the engines when they sell them. The aluminum housing Hanger nine filter is the best I have found heres a link:

http://horizon.hobbyshopnow.com/prod...sp?prod=HAN143

Russ probably carries them or will get you one.


Later,

Mutare23,

I'm no expert on the matter, but here's an excerpt from a discussion on the subject from the NSRCA (pattern) mailing list.

From Eric Henderson:

Ahhh! the wonders (or secrets) of engine behavior. Oil lubricates and
reduces friction to a point. But when included in the fuel itself it
does not necessarily cool. More fuel will cool.

The OS 1.40 runs so well on Coolpower because it has 17% oil. Higher oil
contents makes you turn the needle in to get more power and then edges
you towards "too lean" and the dreaded heat barrier. Less oil gives you
cleaner burn with the more volume of methanol and nitro present. The
heat is not removed by the excess oil. It does not burn nor does it give
any power.

Eric.

...
From Tom:
Great answer Eric, the increased methanol actually does the cooling.

Keith B

Thanks for another really interesting insight.

I suppose you can say that I'm just an old stick in the mud. I've always run 20% Coolpower oil in my own mixes. (Makes the mixing calculations easy for someone who isnt too bright) and also something about old habits die hard.

What I do know is that I have seen plenty of people fry engines when they have low oil contents and screw the needle too hard, or for what ever reason have a lean run and just keep going in hope.

I've never had an engine failure from 'cooking it' (touch wood), but I have warn them out from having huge flying hours (Up to 2,500 flights) prior to an International competition.

I will now take out a model and give it a run, maybe short, on a lower content oil content and see if I can notice an imporvement, or if as I suspect, I will just chicken out and go back to what I know best

Thanks again

Phil

This theroy of less oil I can definatly vouch for having played with tuning two stroke motorcycle engines.
I shouldn't say less is better what I should be saying is the right amount is what you need.
Next question is what is the right amount? Now this is really difiult to find....with a M/C you can just whip the spark plug out and check the colour for quality of burn and measure temp....unfortunately this does not work even with the lager glow engines due to the way they burn.
From my experience with M/C if you put to much oil in what happens is this requires you to run leaner as Mr Henderson says and this leads to heat siezure.

So I guess the qustions being raised here are what is the oil content that we should be running in these big strokers for max power/efficieny and how can we find that by trial and error......without killing engines????

Is there an "OS/Webra man!" out there that can confirm a recomended content so we have a chance??

Do the manufacturers Webra/OS allready put a safty factor in with there recomended value of oil content therfore taking us close to a "Lean Heat" situation??

The only info that I have found is people running a so called "Safe" amount of oil17% plus, this would pose the question what is safer, Lower oil content?

Mmmm lots of questions Guys
Lets hope all the answers are out there?

Richard

Hay KeithB . I bet you thought the Webra thread was dead . I have a new one I am trying to get to run well. I have about 30 flights on it. I have a Bolly 140 pipe on it at 24 In. to the 1 st baffle and 30 inches overall length. I have a good idle and ok transition most of the time my problem is it seems to want to lean out on up lines and I cant open the main needle enough to change this without messing up other things. I have read your input on the pump and would like to know if I should Increase or Decrease settings or maby not change them at all ? it I seemes to me that I need more fuel on the big pulls and vertical lines but I may not understand the pump as it relates to high speed needle setting. BTW the main needle is only a turn out. I will be in pretty good shape if I can fix the vertical problems . Any advbise would be great. Oh yea Pro mix 2 carb.
Thanks Kirk

Kirk, Im no pro but I have been running the Webra 145/160 for a few years and it sounds like it's lean in the middle most likely caused by a bad pump. You can try to turn the the pump adjustment in about a half turn and see what happens, shorten the pipe a little will richen the mid range as well. If you want to take take the quick way to a good running webra remove the pump guts from the back plate and throw them in the trash, drill and tap the center hole in the back plate for a pressure nipple and buy the Perry VP30 pump. You also have to plug the two old pump mounting holes in the back plate, I have a simple way of doing this if you decide to use the perry pump, let me know. I found the Webra pump unreliable at best, one hot run and its trash. If you continue to run it like this the con rod bushing will wear very fast. If you pull the back plate/ pump assem. out you will see that the piston skirt is banging on the back plate when the crank is at bottom dead center, this makes matters worse. After installing the Perry pump you will find the Webra very reliable and with good power. Your needle setting is about right @ one turn out and will end up @ about 3/4 out with the perry and fully broken in. Run the OS type F plug to keep things lit. The needle seat on the ProMix carb will wear over time due to vibration, I had to replace mine every couple hundred runs so keep that in mind if she start running richs down the road. Also the rear bearing is only good for 40-50 flights, I install the stainless bearing that Boca offers. Good air flow around the crank case helps with bearing wear as well. Hope this helps.

KGSS28,

I owned the Webra that was commented on in this post several years ago. Horizon told me the Webra pump was a problem due to inconsistencies in quality control. That's why some ran good while others made you pull your hair. I have learned from flying with an expert engine man here in Phoenix always run a 1oz header tank on all pumped engines. This takes some of the load off the pump and makes for a more consistent run down to the last oz of fuel. I have incorp this into my latest OS140 setup and I can tell the difference in the way the engine performs. The engine seems to strain less probably because the fuel is pulled from the header tank 3 inches from the carb instead of 12 inches from the CG location. This would be a easy thing to try vrs tinkering with the pump settings. I've been there and done that on a Webra and ended up solving nothing. Good luck and remember - make small adjustments at a time if you mess with the pump. Webra's are very intollerant of heat so make sure your cowling provides excellent airflow.

M Austin

Kirk,

Man, talk about a flashback, this thread was nearly four years ago!

I have several initial questions before I can give an informed opinion:

1. Is the engine new, or did someone before you run it?

2. If new, where did you get it and when was it initially purchased?

3. Have you made any adjustments to the pump?

4. Did it run better when it was newer, or has it always sagged on up lines (in other words, has it deteriorated)?

5. Have you, or anyone else, made any changes to the engine, for example replacing the bearings?

6. What fuel are you running in it?

7. Have you tried the low-end test from post #21? If so what was the result? "The low end normally needs adjusting. To do this let it idle at around 1900 to 2000 rpm if it keeps dying it's probably too lean (which normally isn't the case from the factory). Once you've got it successfully idling at 2K or so let it sit and idle for about 20 or 30 seconds then try revving it up. If it sputters and has trouble revving up then the low end is too rich. Reduce the low-end needle 1/8 turn at a time until you can go from idle to wide open without it sputtering. "

8. Another good test is to let it run at the mid-range (around 4500 to 5000 RPM) for about 45 seconds then go to full throttle. If it chokes and sputters this normally indicates that the high-end needle is too rich. If you've done this, what is the result?

If you can answer these questions it will be the first step towards solving your problem.

For the record, and with all due respect, I whole-heartedly disagree with Brian's comment about trashing the pump and using a Perry pump. I've run the Webra 1.45 for five or so years now in hot, cold and in between weather and there's absolutely no reason to use a third party pump. Once you get the motor tuned they run great with the standard pump.

Regarding M Austin's comment about inconsistent pump quality, and possibly why Brian feels as he does, there is some validity to this comment because one of my Webras did have a different pump membrane, which got brittle relatively quickly. However, I think this was an exception rather than a rule as I've seen the insides of pumps from many years of Webras and all but this one had the same (good) membrane material (this is why I asked when your Webra was originally purchased). Once I switch the membrane I had no more problems. Actually the pump is an extremely simple device and should hold up for hundreds of flights.

Keith B

From my experience of both Webra, and OS, backplate-mounted pumps,they'll both often keep pumping even when the diaphragms start to break up-----so it's quite a good insurance to have an extra, fine, filter, installed between the pump and the carb, in addition to the usual one between the tank and the pump....

And the Webra one does seem to be more sensitive to overheated runs than the OS, just my observation.

Keith

1) New in box

2) Came from friend thinks bought about 4 years ago.

3) yes I turned the pump in very slightly thinking it was lean on the up lines. Have not flown yet . also when you hold the nose up it does slow down some instead of speeding up like most engines do.

4) It has run about the same the whole time I have had several dead sticks and have had as many flights where it ran pretty well landed and taxied back. and a couple runs where it displayed that Webra power in the verticals.

5) Never been apart.

6) Power Master 15 %

7) Have got good idle and transition after low speed adjustment.

8) Yes will do this if Main needle is to rich I am at just over 1 turn out.

OK I think thats all other than that it flip starts easy will idle as long as you want and transition now after low speed adjustment. What should the break in period be and should it act strange at times while in the new stage?

Thanks for all your help PS I thought you would be shocked at the revival of this thread

More Info added Friday.

Flew today and wow what a difference the adjustments made . It ran today 5 flights with almost no transition gurgle and only very slight when it did and not every time mostly when going from mid to full throttle . The vertical is unlimited with acceleration upward , throttle is easy to manage seems like speed in constant and transition on and off of the pipe is smooth most manuvers flown 1/2 to 3/4 throttle no dead sticks and perfect idle flip start 1 st flip every time.

So all the changes are as follows leaned Low speed about 3/4 turn to get transition, removed Dubro external fuel valve filler now run straight to pump adjusted pump in very slightly in, opened main needle valve to about 1 and 1/2 turns out.

Again a remarkable difference after these adjustments I think we are on the right track I just hope it will stay this way.

Thanks Kirk

"For the record, and with all due respect, I whole-heartedly disagree with Brian's comment about trashing the pump and using a Perry pump. I've run the Webra 1.45 for five or so years now in hot, cold and in between weather and there's absolutely no reason to use a third party pump. Once you get the motor tuned they run great with the standard pump.

Regarding M Austin's comment about inconsistent pump quality, and possibly why Brian feels as he does, there is some validity to this comment because one of my Webras did have a different pump membrane, which got brittle relatively quickly. However, I think this was an exception rather than a rule as I've seen the insides of pumps from many years of Webras and all but this one had the same (good) membrane material (this is why I asked when your Webra was originally purchased). Once I switch the membrane I had no more problems. Actually the pump is an extremely simple device and should hold up for hundreds of flights."

Keith B






Yes Keith you have a point all my Webra's are at least three years old [ three 145's and a 160 ]. The 160 pump ran with no problems for two years [ broke the crank case at d3 champs last year ] and was the newest of the four. All three 145's had pump failures within a short time. I'm not downing Webra's as they served me well for years but I have allways disliked the pump just due to my personal experiance and have had good luck running them with the Perry. The new pumps may be more reliable.

For what it's worth: I fought with this engine for an entire season and could not get it to run properly; I even sent it to Horizon to have the pump checked out. I finally installed a Perry pump and the engine was immediately easy to operate and it runs fine; very predictable. This is the fourth year I've had it and it has had one bearing change, over 350 flights with no major problems. (I did have a hard time diagnosing the problem when the bearing went bad.) (Mueller header/Grieve pipe.)

For me the same experience as Boduka. After changing to a perry pump the engine has been performing great and super reliable.

Jock

I'm having problems with the engine being sluggish until it comes on the pipe which it starts about 75% throttle. It is very hard to have any throttle management. Someone said they thought the pipe was short. I have not measured it from the glow plug yet and I'm not really sure what measurement it should be at. My engine has the greves pipe running F type plug. The engine seems to idel real well but it is real weak in the mid throttle area, but when it come on the pipe it has no problem going vertical with a 2 meter eclipse. Any suggestion would greatly appreciated.