Cermark Pitts structual failures ?
08-13-2002, 07:25 PM
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Cermark Pitts structual failures ?
Sure enough. You know that's how threads go sometimes, though...they tends to wander a bit!
Funny, though, that your TT120 IS within the recommended range.
Like you said, though, now you know that it was probably not your gear.
Funny, though, that your TT120 IS within the recommended range.
Like you said, though, now you know that it was probably not your gear.
08-14-2002, 02:57 AM
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Good to see my old Girl is still around...
TT2...
Your Pitts is my old bird. Good to see she is still flying. I sold her a little over a year ago to Mr. Elder. It is a wonderful performer on the Saito 150 and flies even better since I clipped the wings off square.
I have some pics on a photo CD of her with Sean D. Tucker, myself and his full scale Challenger the day he autographed it for me. Send me a note off forum and I'll zap the pics to you if I can find the CD.
It brought a smile to my face to see the old girl again!
Take care of her.
Jon
Your Pitts is my old bird. Good to see she is still flying. I sold her a little over a year ago to Mr. Elder. It is a wonderful performer on the Saito 150 and flies even better since I clipped the wings off square.
I have some pics on a photo CD of her with Sean D. Tucker, myself and his full scale Challenger the day he autographed it for me. Send me a note off forum and I'll zap the pics to you if I can find the CD.
It brought a smile to my face to see the old girl again!
Take care of her.
Jon
08-15-2002, 02:55 AM
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Cermark Pitts structual failures ?
Please Please will somebody say something good about this plane. I just purchased one about 2 weeks ago (close out sale, surprise, surprise). It sure is a beautiful plane, think I will leave the YS 140-L on the shelf on this one, and will go with a Surpass 120 III pumper or YS 91 (how about a Saito 100???).
EasyTiger and jbrundt I understand what your saying, but Cermark has another problem if your saying the Saito 150 is to much power for the Pitts, when in just about every picture in their instruction booklet they show what looks like a YS 120, they even talk about using and show a 140-L. Now with out stepping on any Saito toes, you can't compare a Saito 150 to a YS 140-L.
EasyTiger and jbrundt I understand what your saying, but Cermark has another problem if your saying the Saito 150 is to much power for the Pitts, when in just about every picture in their instruction booklet they show what looks like a YS 120, they even talk about using and show a 140-L. Now with out stepping on any Saito toes, you can't compare a Saito 150 to a YS 140-L.
08-15-2002, 03:28 PM
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Cermark Pitts
I had one of these powered by an RCS 140. The engine would turn a 17-8 APC about 9000 RPM in the air so I don't think it was under powered.
I flew it about 1&1/2 years until I dumb thumbed it into the ground.
The only mods made were to strengthen the cabane structure at the top and some repair of the LG that I kept ripping off with my bad landings.
Its a great airplane. Its lightness covered a lot of my flying errors.
I flew it about 1&1/2 years until I dumb thumbed it into the ground.
The only mods made were to strengthen the cabane structure at the top and some repair of the LG that I kept ripping off with my bad landings.
Its a great airplane. Its lightness covered a lot of my flying errors.
08-15-2002, 09:58 PM
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CERMARK PITTS
propwash-don
please dont let this plane worry you, i have been flying mine for
3 long hard seasons with a YS-120FZ on the front turning an 18x6
carbon fiber and have only had 2 problems with it. the first was
probably was my fault doing a half throttle blender and blowing
the firewall apart and breaking a few hinges on the tail section,
luck was with us that day-got her back on the ground in one piece. the second was just a few months ago at a flyin in
owensboro, ky where on the first flight, the pull-pull cables
broke on the down elevator side..... took 2-3 attempts and luck
was with us once again, got the pitts back on the ground and
taxied back to find i had no down elevator other than a bounce in
the propwash. i was just on the phone with CERMARK yesterday
trying to get them to check the warehouse and see if they could
piece me together a back up out of the replacement parts they have for this plane. the people there have always helped me with
any information or replacement parts at a reasonable price for the pitts(including a manual for the plane they sent me at no charge). dont let it bother you to fly this plane, i done very little
as far as beefing mine up, tri-stocked eveything around the firewall area and even into the fuse, made the wing saddle a little
thicker with 1/4 inch balsa glued to the inside and the cut to fit the wing. other than that, fly the you know what out of it or give
me a shout if you would be willing to sell or trade. i have a spare
YS taking a break and not doing anything at the moment. i have had more problems with my G/P PITTS than with the CERMARK. the people at G/P are also great people to work with. after 25-30
flights on the G/P my firewall was coming apart and luckily while
i was taking the bird apart in the shop, i had found that one of the
90 degree L shaped brackets that is bolted to the top wing was broke connecting the top wing to the cabane struts(called G/P and talked with a nice lady in customer service and she sent me brand new ones).
hope i was some help don
pittsman
please dont let this plane worry you, i have been flying mine for
3 long hard seasons with a YS-120FZ on the front turning an 18x6
carbon fiber and have only had 2 problems with it. the first was
probably was my fault doing a half throttle blender and blowing
the firewall apart and breaking a few hinges on the tail section,
luck was with us that day-got her back on the ground in one piece. the second was just a few months ago at a flyin in
owensboro, ky where on the first flight, the pull-pull cables
broke on the down elevator side..... took 2-3 attempts and luck
was with us once again, got the pitts back on the ground and
taxied back to find i had no down elevator other than a bounce in
the propwash. i was just on the phone with CERMARK yesterday
trying to get them to check the warehouse and see if they could
piece me together a back up out of the replacement parts they have for this plane. the people there have always helped me with
any information or replacement parts at a reasonable price for the pitts(including a manual for the plane they sent me at no charge). dont let it bother you to fly this plane, i done very little
as far as beefing mine up, tri-stocked eveything around the firewall area and even into the fuse, made the wing saddle a little
thicker with 1/4 inch balsa glued to the inside and the cut to fit the wing. other than that, fly the you know what out of it or give
me a shout if you would be willing to sell or trade. i have a spare
YS taking a break and not doing anything at the moment. i have had more problems with my G/P PITTS than with the CERMARK. the people at G/P are also great people to work with. after 25-30
flights on the G/P my firewall was coming apart and luckily while
i was taking the bird apart in the shop, i had found that one of the
90 degree L shaped brackets that is bolted to the top wing was broke connecting the top wing to the cabane struts(called G/P and talked with a nice lady in customer service and she sent me brand new ones).
hope i was some help don
pittsman
08-16-2002, 01:27 PM
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Cermark Pitts structual failures ?
Thanks pittsman, you have helped put my mind at ease. I've been 'sitting' on this plane too long and it's time it went up. I'll check to make sure the firewall has been beefed and if not, I'll pin it and back it up with some tri-stock and carbon fiber.
Maiden flight Sunday...weather permitting.
-Tom
Maiden flight Sunday...weather permitting.
-Tom
08-16-2002, 04:35 PM
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Cermark Pitts structual failures ?
Hello Guys
Ive had the Cermark Pitts for quite sometime now. Two as a matter of fact. The first one was great and had no problems, in fact I believe its one of the best ARFs out there! At first I had a Lowly Magmum 120 and it was ok but not really authoritive. I had a Saito 150 stroker and mounted that. WOW, it was a blast untill the saito blew a conrod and I lost it on a turn to the runway! One turn was all but it was too much! Damn pilot error on my part! I felt very badly as my wife and daughter bought this bird for me as a surprise! Add the fact I loved how it flew and I bought another.
This time I decided to try my G-23 gasser. WoW, It hated that mill! Too damn heavy and it showed badly on landing! Had to come in really fast or the sink rate was too high to have landed without damage!
So I did the smart thing for a change... I got an OS 120 surpass!
It loves this setup and does anything ya want except torque rolls and I believe thats because of balance, prop and me!
I did do some bracing from the Stab to forward of the cockpit with Balsa and carbon fiber.
It can do the wildest snaps and lomcevockes( cant spell that word
) . One time I tried to fly it on a pretty windy day. It was off the runway before I was ready and hangin on the prop. My fingers were on fire as it slamed the runway 4, Yes 4, times and it was 3 circuits to trying to land it! Finaly on the third landing I held it down as it blasted the runway on its belly! The damage was Cracked wheelpants, scrapes FLAT against the bottom of the Landing gear and small impressions in the underside of the bottom wing. The Bird IS still flying to this day with only VERY minor restraightning to the gear!
This bird is one fine flying Pitts and IT CAN TAKE A BEATING!
My Hats off to Dave Patrick
Ive had the Cermark Pitts for quite sometime now. Two as a matter of fact. The first one was great and had no problems, in fact I believe its one of the best ARFs out there! At first I had a Lowly Magmum 120 and it was ok but not really authoritive. I had a Saito 150 stroker and mounted that. WOW, it was a blast untill the saito blew a conrod and I lost it on a turn to the runway! One turn was all but it was too much! Damn pilot error on my part! I felt very badly as my wife and daughter bought this bird for me as a surprise! Add the fact I loved how it flew and I bought another.
This time I decided to try my G-23 gasser. WoW, It hated that mill! Too damn heavy and it showed badly on landing! Had to come in really fast or the sink rate was too high to have landed without damage!
So I did the smart thing for a change... I got an OS 120 surpass!
It loves this setup and does anything ya want except torque rolls and I believe thats because of balance, prop and me!
I did do some bracing from the Stab to forward of the cockpit with Balsa and carbon fiber.
It can do the wildest snaps and lomcevockes( cant spell that word
) . One time I tried to fly it on a pretty windy day. It was off the runway before I was ready and hangin on the prop. My fingers were on fire as it slamed the runway 4, Yes 4, times and it was 3 circuits to trying to land it! Finaly on the third landing I held it down as it blasted the runway on its belly! The damage was Cracked wheelpants, scrapes FLAT against the bottom of the Landing gear and small impressions in the underside of the bottom wing. The Bird IS still flying to this day with only VERY minor restraightning to the gear!This bird is one fine flying Pitts and IT CAN TAKE A BEATING!
My Hats off to Dave Patrick
08-16-2002, 11:26 PM
#36
Cermark Pitts structual failures ?
My Cermark Pitts "blew apart" on me 2 seasons ago due to aileron flutter while in a gentle inverted pass at moderate speed mid field.
I could clearly see that the flutter began on the top wing ( which was on the bottom because the aircraft was inverted). In a split second the aircraft broke up and buried itself mid field.
The engine was a Saito 150 however , low throttle and moderate speed was involved.
It is difficult to say whether the flutter originated in the ailerons or the cabane mount area.
I had about 50 flights on the airplane before this incident.
I did contact Cermark at the time and made them aware of the occurance.
I've since read countless reports of the same failure.
I would never buy another cermark arf again.
Mike
I could clearly see that the flutter began on the top wing ( which was on the bottom because the aircraft was inverted). In a split second the aircraft broke up and buried itself mid field.
The engine was a Saito 150 however , low throttle and moderate speed was involved.
It is difficult to say whether the flutter originated in the ailerons or the cabane mount area.
I had about 50 flights on the airplane before this incident.
I did contact Cermark at the time and made them aware of the occurance.
I've since read countless reports of the same failure.
I would never buy another cermark arf again.
Mike
08-17-2002, 04:13 AM
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Cermark Pitts structual failures ?
More bad news? OK, can you give us specifics as to the hardware configuration etc.? Upon inspection of the wreckage, was the center cabane blown apart? God...please tell me that the upper wing bolts didn't pull through the wood!!!
HELP! I'm nervous...
So goes the question: Do I fly it like I'm going to sell it, or do I fly it like I'm going to keep it?
-Tom
HELP! I'm nervous...
So goes the question: Do I fly it like I'm going to sell it, or do I fly it like I'm going to keep it?
-Tom
08-17-2002, 10:34 AM
#38
pitts
tom,
Wish I could tell u if the cabane bolts let go or not but, there was so much damage that I really can't say if the crash was due to a cabane failure or aileron flutter.
I can tell u that the entire top wing began to flutter and the airplane broke up so fast , I had no chance to save it.
What surprised me was the speed at which all this occured. As stated in my previous post this was a gentle inverted pass.
The airplane had held up to many high g maneuvers on the 50 or so prior flights.
I was using Hitec 605's all round , the gears were stripped on both aileron servo's.
All hardware was replaced with good stuff ( not the junk in the kit)
As stated , this was 2 flying seasons ago, my Pitts was the original version, the fuselage and wings were packed in two separate boxes. ( I believe eveything's in one box now).
That's about all I can think of now.
I felt Cermark didn't support the product and that's why I won't buy another item from them.
Hope this helps
Mike
Wish I could tell u if the cabane bolts let go or not but, there was so much damage that I really can't say if the crash was due to a cabane failure or aileron flutter.
I can tell u that the entire top wing began to flutter and the airplane broke up so fast , I had no chance to save it.
What surprised me was the speed at which all this occured. As stated in my previous post this was a gentle inverted pass.
The airplane had held up to many high g maneuvers on the 50 or so prior flights.
I was using Hitec 605's all round , the gears were stripped on both aileron servo's.
All hardware was replaced with good stuff ( not the junk in the kit)
As stated , this was 2 flying seasons ago, my Pitts was the original version, the fuselage and wings were packed in two separate boxes. ( I believe eveything's in one box now).
That's about all I can think of now.
I felt Cermark didn't support the product and that's why I won't buy another item from them.
Hope this helps
Mike
08-18-2002, 04:26 AM
#39
Cermark Pitts structual failures ?
I put 100+ flights on my Cermark Pitts without any failures, but I DID rework the cabane top by including some 1/32" ply to gusset the top wing mounting blocks which had a disturbing tendency to separate in flight. I also doubled the ply plate in the wings where the top wing mounting bolts attach because there were reports of the stock plate failing.
I had a saito 150 in mine and don't agree that was over powering it, because when Dave patrick says 120 four-stroke he means a YS 120 FZ which easily puts out the same power as a Saito 150!
There were sevral other quality issues w/ my plane which I documented in this review: http://webpages.charter.net/rcfu/Kit...ermarkS2B.html
I had a saito 150 in mine and don't agree that was over powering it, because when Dave patrick says 120 four-stroke he means a YS 120 FZ which easily puts out the same power as a Saito 150!
There were sevral other quality issues w/ my plane which I documented in this review: http://webpages.charter.net/rcfu/Kit...ermarkS2B.html
08-18-2002, 04:42 PM
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Cermark Pitts structual failures ?
I also doubled the ply plate in the wings where the top wing mounting bolts attach because there were reports of the stock plate failing
Thanks,
-Tom
08-19-2002, 09:21 PM
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Nothing wrong with mine.
I have been flying my Cermark Pitts for over two years now, and just inspected it yesterday. I like to tear it down about every six months to check things out. Other than a few wearing parts, everything looked in good order. The vibration from the engine appears to be widening the holes in the cowl where the mounting bolts hold it onto the airframe, the wheel pants had a few cracks in them from many landings on out bumpy grass pasture, and the axel appears to have broken loose inside the mounting nut. (might be the cause of some of the cracks) she had minor mars from transport, and worst of all, after two and a half years, some of the striping tape has come loose on the lower right wing tip. Cabanes and inner structure glue joints look intact.
The upper wing plywood plate looks fine, although you can see an impression where the washer squashes down. Looks normal.
BTW LuvBipes, if you beef up the plate from the bottom with 1/8 ply, doesn't that shim the wing in the center making the outer struts pull down harder, and focus more stress on the center joint(s)? Seems to me the better way to do it would be to reinforce it from the top of the plate. If I added the reinforcement plate to the bottom, I would have to bend the wing a little to get it to attach at the struts. Am I missing something?
Flys great with a YS120. If you run the special 22% YS blend fuel from Byron you get a great smoke show as well. Love to see the Pitts tailslide back through the smoke cloud.
Dan Gellner
The upper wing plywood plate looks fine, although you can see an impression where the washer squashes down. Looks normal.
BTW LuvBipes, if you beef up the plate from the bottom with 1/8 ply, doesn't that shim the wing in the center making the outer struts pull down harder, and focus more stress on the center joint(s)? Seems to me the better way to do it would be to reinforce it from the top of the plate. If I added the reinforcement plate to the bottom, I would have to bend the wing a little to get it to attach at the struts. Am I missing something?
Flys great with a YS120. If you run the special 22% YS blend fuel from Byron you get a great smoke show as well. Love to see the Pitts tailslide back through the smoke cloud.
Dan Gellner
08-20-2002, 05:51 PM
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Ooooooh I see!!!
I see what you're saying. I just didn't think of it because those adjustable anchors in mine are now.....epoxied in place, so it will be tougher for me to retro fit it (maybe if I heat them up). Great idea if you are still assembling.
1/8 is fine, the difference in weight is worth the extra beef.
Dan
1/8 is fine, the difference in weight is worth the extra beef.
Dan
07-26-2004, 10:49 PM
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RE: Cermark Pitts structual failures ?
I really like my original CERMARK Pitts. I power it with a OS FX 91. Usually fly it at quarter throtle.
It flies great! Take offs are easy (just keep up with that rudder) so are the landings.
Set up: all four ailerons powered by two 531 servos (carbon fiber rod to connect top to bottom).
I built in an extra support for the landing gear. Welding wire from the wheel pants hole to the
mounting hole on each side (cris cross support). This is due to the flex in the fuselage when the gear bends under pressure.
I chose the pull-pull for all tail surfaces. So far, works fine. I mounted the throttle servo in the engine compartment on the firewall (like the GP Pitts). Works fine. Be sure to shield from engine heat.
I included wires to the upper wing to stay in scale. They sure make noise in flight. I am considering pulling the wires off.
So far no flutter. Based upon the extended linkage, I'm watching it carefully.
I also included a Sullivan tail wheel. Best system I've seen for a tail wheel!!!
I also wired the vertical and horizontal stabalizers with piano wire - tipped with soldered brass tubing - flattened tip and fastened through stabalizer surface with bolts.
I'll keep you posted.
Stan[img][/img]
It flies great! Take offs are easy (just keep up with that rudder) so are the landings.
Set up: all four ailerons powered by two 531 servos (carbon fiber rod to connect top to bottom).
I built in an extra support for the landing gear. Welding wire from the wheel pants hole to the
mounting hole on each side (cris cross support). This is due to the flex in the fuselage when the gear bends under pressure.
I chose the pull-pull for all tail surfaces. So far, works fine. I mounted the throttle servo in the engine compartment on the firewall (like the GP Pitts). Works fine. Be sure to shield from engine heat.
I included wires to the upper wing to stay in scale. They sure make noise in flight. I am considering pulling the wires off.
So far no flutter. Based upon the extended linkage, I'm watching it carefully.
I also included a Sullivan tail wheel. Best system I've seen for a tail wheel!!!
I also wired the vertical and horizontal stabalizers with piano wire - tipped with soldered brass tubing - flattened tip and fastened through stabalizer surface with bolts.
I'll keep you posted.
Stan[img][/img]
