Cermark MB339 Struts
 

Does anyone out there have available or any ideas where I can get some working struts for my MB339. Any info would be greatly appreciated. Thanks
Jim

MB-339 Struts
 

I recently ordered a pair of Intairco struts from Darryl Usher at http://acsip.com/~dgu/mod1.html . They haven't arrived yet, but when they do, I'd be glad to post a report.

I got the idea from another post here on RCU:

http://www.rcuniverse.com/showthread.php?s=&threadid=589399&forumid=26&highl ight=mb339+intairco

Here's the website for Intairco, an Australian company:

www.intairco.net/

Click on "Jet Products" in the menu on the left and look for the link to "IAC NOSE GEAR OLEO STRUT"

Good Luck,

Davidd

MB339 Struts
 

David ,
Thank you for the info you provided. When you get yours installed , please let me know how they are!! I think the struts will help with the little bit o'bounce you can get on the MB339.
Thanks again,
Jim

Who has them
 

Has anyone tried them yet? How do they hold up? The only picture on their web site makes the scissor look a little weak.



Turbulence

Count me in
 

Struts would be perfect

P.Richards aka S.W.A.T. TEAM

Struts
 

Ralph,

Check out the second thread I linked to in my post, above. Apparently this guy tried them with good success. Thud_Driver also ordered a pair along with mine, so hopefully we'll have some reports for you some time soon.

David

STRUTS?
 

After putting three flights on my MB-339, I want those struts, but first, Does Anyone got an update on the Struts? anyone out there using them? how do they fit? function O.K.?

Turbulence

Struts
 

Ralph,

We're still waiting, maybe this week. If so, I'll try to fly them in within the next weekend or two. They are not cheap. The delivered price is going to be right at $145 for the pair. Until I see them, I'm still going to be concerned about the strength of the forks. Side loads under braking with a 20 lb airplane on landing are large - that's how I broke my Eurokit fork. Too bad Eurokit stuff isn't easy to come by, at $26 a pair I could replace a lot of struts for what the Intairco's cost. Anyway, a trailing arm oleo fixes the Macchi Bounce so I'm expecting these stuts will work fine.

Rick

Other Options?
 

Now that mine is airborne, I am hot for parts to make it better. I am talking with Steve at Top Gun about making me some custom Top Cat struts like he did before for my larger MB-339, Those handle my 30lb MB-339 very nice, but are a little on the larger side for the Cermark one. If I can get Steve to relocate the Axle mount/hole then they will fit great, they are more than strong enough and best of all can be here in a couple of days instread of months. I just went back to the Intairco website and could not locate the struts anymore?? Another option would be to have Sierra Precision Make me some. It is not that hard for someone with the tools and know-how we just have to give them an incentive to do so (don't include me on the list of know-how or tools) but if Sierra can make some custom struts like the one he sells for Scale Sea Fury Fork for tail wheel, all we need to figure out how make them strong (or thick enough) to handle the weight.


Darrell from SP and Steve from TG are you lurking?? plenty of these planes out there.

Turbulence
[email protected]

Struts
 

Ralph,

I just picked up the Intairco struts from Flanker. I'd suggest you follow through with TGA for custom struts. The forks might take it on a DF but they're not likely to last on my heavier turbine MB-339. The strut itself looks like it'll never break but the fork looks too light weight. Have to remember it was made for nosegears and not mains.

My P-80 is in for a routine checkup, so whenever it gets back I'll try them out.

Rick

Not Good
 

I checked with Top Gun and the price was higher. $270 for the mains. Before I spent my money I took my struts out of my other Aermachi and I could not get them to work. The struts from TG are just too big, very strong, but too big.

My struts are already cut down to 4 inches (strut only, nt including the nuckle). I will take another look tomorrow at an idea that just popped into me as I write this. I can cut maybe up to half inch more tops on the strut, Relocate the axle mounting hole about almost half and inch and last but not least, shortent the strut tha tconnects to the nuckle (part of the strut that gives you the travel limit/stop) But again since I need them for the other plane, I am hesitante to jsut cut them apart for nothing


Ralph

Struts
 

I checked the Intairco struts against both the MB-339 and my Jim Fox Hawk and the fit is still a bit of a problem on both. These are actually made to have a 3/16" wire soldered into the brass strut fitting and have that go into the retract unit. The struts won't come anywhere close to fitting if you mount them that way. The strut diameter is 1/2" which means I can discard the brass fitting and use my Robart 630 retract units, which are large. The Springair 400 series would also work. Neither is a good choice size wise for the installation, but I really don't want to spend another chunk of change on this airplane anyway, so I'll make do. My engine is still back at JetCat so it'll be awhile until I fly them.

Actually, the best bet is to cut open the wing, move the gear mounts back, make a new gear well, use regular straight stuts, close it up and repaint. Bet you could do it in a weekend, except the paint.

Cermark MB339 Struts
 

Is the reason for the landing 'hop' the fact that the struts have a 'dog leg' bent in them, thereby making them spring loaded?

I have the DL kit and angled the wire gear back, with no bend in them, thinking this may help, but may still have the issue, since it may want to recoil, just the same.
I plan to fly using a Wren MW-54 engine.
Jim

O'Well
 

I keep trying to see if I come up with anything. In the mean time, Rick, Ken and I should be at Prado Sunday around 1:00 and Also on Tuesday


Turbulence

Hop
 

Ralph - thanks for the invite but I'm still short an engine so I'm doing props in the desert today. We're doing combat planes tommorrow if you want to come up.

JKS - my theory is that the dogleg wire struts turn them into a "pogo stick" and seem to add energy vertically rather than smooth out the landing. It rarely turns out to be a hop when it starts but more like a basket ball. The spring gear just doesn't always damp out. You also can get some serious pitch excursions that can cause damage. Usually you can't stop it using the normal techniques of adding power and holding back stick. Mostly you're just a spectator.

Cermark MB339 Struts
 

Thud, that's what I thought; pogo stick is a good anlogy.
I'm going to look into your idea of wing surgery, since mine is only sheeted not yet finished.
How would you proceed?
Thanks,
Jim

Cermark MB339 Struts
 

JKS - I have the ARF and there aren't many ribs in there. So one could presumably use a zona saw and cut the sheeting and maybe detach it without damaging it too badly. Then you'd have to cut out the retract plate and install a new one with new braces, etc., and put it back together. I'd make a new wheel well - sometimes you can lay one up over a plastic cup bottom or just use the cup.

I'd also think about making the strut length longer as I think the airplane sits too low and has a problem with ground effect. 3/8" Robart oleos would probably be ok with Robart 550 retract units. I use the 550's on my TopCat and they take more abuse than the Springair units.

Intairco struts
 

Turbulence & Flanker,

I've got the Intairco struts mounted now. The cutting & fitting wasn't that bad on the wing. I had to cut ~1/2" off the top of the strut which destroyed any chance of using the oil damping feature. Also had to grind down the internal threaded rod damper a bit to keep it from hitting the bottom of the strut mount. As installed, the wheels do sort of center in the wheel wells. I'm ok since my tires are pretty worn but new tires might be a close fit.

So the Robart 630 retract units appear massive, the strut appears massive and the fork looks like something for a .40 trainer (it's for nosegears). Fly it next week. I've got enough flights on the engine now since back from service so I'll make the switch Monday or Tuesday. Can't do it this weekend.

Rick

Struts working.....
 

Went out in the wind today and did 2 flights with 4 landings altogether. Three to a full stop and one touch and go. All the landings were good with no sign of a bounce. I did some moderate braking a couple times with no issues. I had almost forgotten how effortless this airplane is to fly. I did all the takeoff's at less than half throttle and never pushed it any higher. I used half flaps for landing (about 3/4" down) and carried power due to the wind.

Now it's over to endurance testing so I'll see about a bunch of flights the rest of the week. If they last these struts might be the answer. Too bad Cermark doesn't offer a set for this airplane.

More Landings
 

Ok, 14 flights and about 20 landings this week. Everything from smooth to smack down. The struts seem to be holding up. No sign of the classic Macchi Bounce, a few easy to handle skips from a fast touchdown or two.

I'm off scope for a couple weeks, when I get back I'm moving the engine back to the TopCat. The Macchi is getting boring (again).

Curious, I have 130 flights on my ARF now, how many do the rest of you reading this thread have????

Intairco Struts
 

Thud_Driver:

Good to hear the struts worked for you for a few flights. If they can handle your turbine bird, a df bird should do fine.

David

Flights?
 

What flights? compared to you none. I am only up to 10 flights. two of those today after the re-paint. Can you please give me the part numbers for those struts. I am ordering them Mondauy or Tuesday at the latest. My landings are non-bounce/stall type except for today, but I am really tired of the wire struts, then again my plane is problably 3 pounds heavier than most of you ( at least)


Turbulence

Struts
 

Ralph,

Flanker ordered them through Daryl Usher in Oregon. Intairco just changed their web site and their struts page is blank. Don't think there is a part number but you want the short (110mm) nose gear for the Airworld L-39. There is also a long one. There's a picture of them on the Motors & Rotors web site under Jet Turbine Aircraft - Jet Accessories.

http://www.motorsandrotors.com/home.htm

You could e-mail Daryl or Intairco. It took over a month to get them.

PS - my MB-339 weights 17.5 lbs no fuel. The struts are 1/2" diameter so you need Robart 630 or Springair 400 series retract units.

Rick

Struts
 

Ralph,

You can order the struts in pretty much any length you want from 110 mm or higher--but 110 mm is the minimum. I went through Daryl Usher out of courtesy since he's already importing the Intairco wheels.

David

One Week
 

Having seen that you mentioned a one Month Delivery I emailed Intarco directly to find out what the scoop was. I was told if I ordered them now (Friday the 20th) he could ship them out Monday. The email came back to Sunday night. Monday morning I placed the order and the struts arrive this morning. Less than a week. I will butcher the plane sometime this week so I can try to have them ready for Thursday flying.

Turbulence