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Larger Revolver

Old 01-27-2013, 03:59 PM
  #6376
Luchnia
 
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Default RE: Larger Revolver

I forgot to state that I spoke with a fellow flyer yesterday that was helping someone with a new Rev 70 that was just bought and his servo bays were off too, but his was not as bad as some of these others. I think they said it was less than 3/8 inch overall and his wing pins were a little crooked but his wings would mount ok whereas one of mine won't.

It seems that these newer Rev 70s are having some quality control issues which is certainly alarming for a plane coming from Great Planes. I hope this is not the beginning of a trend. A friend of mine recently bought a GP Yak but it was ok, it only had a small dent in the back.

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Old 01-27-2013, 04:19 PM
  #6377
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Default RE: Larger Revolver

FWIW, just looked at my wings and the servo bays are off as well. The reinforcement areas on the aileron did match up okay with the pushrods, so it was not noticeable until I put them next to each other.

Did first flights today of plane with XYZ 20 engine. Plane flew great, as expected. Blustery wind conditions with strong crosswinds. Very impressed with handling of the gusty wind. Flying off a grass field and did several smooth touch and goes on the first two flights. On the third flight had a slightly firmer touchdown, but nothing out of the ordinary, and the auto-ejecting gear tripped putting the plane on its belly rather rudely. Typical holes about the size of pennies punched in the lower wing skin.

Examined the fracture area and could see that what little glue was in the area completely separated cleanly. Now I know why guys say to just wait until it breaks before attempting to reinforce area. Now it is very easy for me to put some epoxy on the joint and get a decent glue bond with the supporting structure.

I purposely chose not to do any reinforcing of the gear before I flew as a test of sorts to see how flimsy it really is in stock condition.

Check out the pic of the plywood gear plate with no glue attached, or any wood that broke off with it.

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Old 01-27-2013, 04:49 PM
  #6378
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Default RE: Larger Revolver


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ORIGINAL: u2fletch


Check out the pic of the plywood gear plate with no glue attached, or any wood that broke off with it.


Man that really pi**es me off. NO GLUE ATTACHED ! What a shame. Zero quality control.[:'(][:'(]

Makes me wonder about the glue joints where I can't see, like inside the wings.

I finally got around to assembling mine. Can't wait to check the quality control on mine ![X(][X(]

The only thing I've found really bad so far is the fiberglass landing gear. I temorarily installed the axles and wheels. The wheels are toed-in about 1". Ouch.....that's really bad as it should be zero inches. When I tried to bend the gear back into position, I heard..........craaaaaack. Damm..........[:@]. In the garbage can they went.

Joe M.
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Old 01-27-2013, 09:30 PM
  #6379
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Default RE: Larger Revolver

Hi All

Reading the posts on the wing servos so I checked mine. They are different and similar to the other posts. I do not know if my first one had the same problem. This would seem to make the problem a world wide issue. I bought this one in November last year and it was probably in the shop for some time before that. I believe that the shop still has one so i might ask the owner to check.

I did not notice when building as the linkage lined up with the reinforcement block. I probably did each wing on different days so not compare them. I always glue the servo boxes into the wings, that has been an issue for a while now.

On the fibreglass landing gear , TNT makes an aluminium version. It has the same same curve as the glass ones and is a two piece set. Much stronger. It is not on their web site , you need to email them and ask.

BC
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Old 01-28-2013, 04:15 AM
  #6380
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ORIGINAL: ShuttleAU

Hi All

Reading the posts on the wing servos so I checked mine. They are different and similar to the other posts. I do not know if my first one had the same problem. This would seem to make the problem a world wide issue. I bought this one in November last year and it was probably in the shop for some time before that. I believe that the shop still has one so i might ask the owner to check.

I did not notice when building as the linkage lined up with the reinforcement block. I probably did each wing on different days so not compare them. I always glue the servo boxes into the wings, that has been an issue for a while now.

On the fibreglass landing gear , TNT makes an aluminium version. It has the same same curve as the glass ones and is a two piece set. Much stronger. It is not on their web site , you need to email them and ask.

BC
It makes sense to me that the servo bays are rarely checked as far as distance from the wing root. If they line up with the reinforcement block then if they were off as far as distance I don't see many even checking this. I know I don't recall ever checking this. The only way I would check it is if it was so noticable that I would see it while installing the wings are putting them in the wing bags or when the plane is held upside down for some reason.

I would wager that the Rev 70 has always had servo bays that are not the same distance. As long as they line up with the block is what really matters and are not crooked. One of mine is somewhat crooked by a substantial amount as can be seen in the measurements. I do like my linkages to be setup with straight lines and mechanically sound, so this is not something I am pleased with. I can certainly shim as needed to fix this, but the question remains, should we be repairing this plane to get it in the air?

Did you buy the TNT landing gear? If so, it would be really nice to see a picture what they look like. I personally like the Rev 70 looks with the swept back factory gear. It adds to the characteristics of the plane while landing and in flight. I have never really had any problems with the fiberglass gear except when I crashed once, but for normal flying they have served me extremely well. I do realize that they would not hold up well under extreme circumstances.

I was looking at possibly buying another GP product but this has made me very hesitant at this point of the game. I am sure GP will make this right though as they do offer good support for their products.
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Old 01-28-2013, 06:47 AM
  #6381
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Default RE: Larger Revolver


Quote:
ORIGINAL: Luchnia

I am sure GP will make this right though as they do offer good support for their products.
Yes, their support is quick to respond and replace. However, in my case the replacement parts were just as bad as the ones I sent in (except the cowl) After my last letter to them they offered to replace again, but I had already assembled the plane and flown it. The reason I buy ARFs is because I want to have it in the air within a week of receiving it. (If I build a KIT then I'm responsible for the quality, and I will be taking my time anyway)
Even if they correct all the problems I don't want to have to keep returning parts until I get the good ones. Especially since I paid shipping to return the parts. The reason I pay over $200 for an ARF this size is I expect the first one I get to be as near perfect as possible.

Fact is, they are having problems with the large Revolver, and something should be done about it before they send them out.
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Old 01-28-2013, 06:55 AM
  #6382
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Default RE: Larger Revolver

Hi

The TNT version copies the same swept back look. Paint them white and it is hard to pick the difference.

BC
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Old 01-28-2013, 07:06 AM
  #6383
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Default RE: Larger Revolver

Not sure I see the advantage of an aluminum version of the stock gear. The problem has never been (from what I know) in the strength of the gear itself. Rather it's the poor design (split) and how it's mounted to the fuse (straight-line blind nuts and not enough strength in the fuse area). The split-construction allows - even invites, the torque of landing to pull the gear apart, and the in-line design of the blind nuts doesn't help much. (though if they were mounted to something solid it probably would not give).

I don't think I've seen or heard of any instances where the gear ITSELF failed.

If this TNT version is also split then what are you gaining? One of the main reasons I use the Dubro gear is due to it's single-piece form, and that it's wide-enough to install new blind nuts in a box, four-corner layout.
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Old 01-28-2013, 07:17 AM
  #6384
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Default RE: Larger Revolver

So true, both times my LG came off it was intact. It comes out in a block from the fuselage[:@]
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Old 01-28-2013, 07:25 AM
  #6385
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Default RE: Larger Revolver

Mike
You are on the mark about the failure point.
Of the several times that the main LG on my R70 has failed, only once was the LG strut damaged, and that was a power-on steep descent caused by loss of elevator linkage. The LG itself is pretty sturdy, and to the extent that the stock gear absorb some shock, that lessens the stress transmitted to the airframe / LG plate.

The ideal LG situation would be a strong LG plate, with shock absorption in the gear. Oh yeah, that is kind of like how full scales are built. Personally, i like the give of the stock FG gear, or the composite dubros that microdon uses. Tying the two sides together with an aluminum plate would allow the shear stress of a hard landing to be shared by all 4 bolts, although i personally have not gone that route. Likewise, it would be possible to add a bolt or two out of line with the existing bolts to make a box pattern, rather than a line pattern.

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Old 01-28-2013, 07:35 AM
  #6386
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Default RE: Larger Revolver


Quote:
ORIGINAL: microdon2


I don't think I've seen or heard of any instances where the gear ITSELF failed.
Actually my gear inself didn't fail, it was simply not made straight.

If it was toed-in about 1/32" that would have been OK and I could have lived with it, but it was toed-in about 1 full inch. When I attempted to straighten it out.........craaaaack !

I found a nice aluminum gear in my spare parts pile........don't know the brand but it should work.

Joe M.
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Old 01-28-2013, 07:41 AM
  #6387
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Joe
What do you mean that it was toed in an inch; the width of the gear strut at the wheel is only about 1.4"; do you mean that the struts were toed in by 30-40 degrees?
I have never seen that.

Some toe in is good for ground handing; as weight shifts to the outer wheel during a ground turn, toe-in helps with the turn, whereas toe-out opposes the turn.
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Old 01-28-2013, 07:58 AM
  #6388
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Default RE: Larger Revolver


Quote:
ORIGINAL: wjcalhoun

Joe
What do you mean that it was toed in an inch; the width of the gear strut at the wheel is only about 1.4''; do you mean that the struts were toed in by 30-40 degrees?
I have never seen that.

Some toe in is good for ground handing; as weight shifts to the outer wheel during a ground turn, toe-in helps with the turn, whereas toe-out opposes the turn.
Thanks, but I understand toe-in principal and I could have lived with a little.

But the bottom of each strut (where the axle attaches and viewed directly from the bottom of each strut) was bent inward about 25 degrees. I placed a tape measure on the tires (at the front of each tire and at the rear of each tire) and found out I had a total of 1" (about 25 degrees on each strut) toe-in..........this is WAY too much. With the toe being that severe inward, it would have probably caused some drag.

Joe M.
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Old 01-28-2013, 08:00 AM
  #6389
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Agree that is too much; your struts were deformed. Does GP have an idea how that happened?
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Old 01-28-2013, 08:04 AM
  #6390
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Default RE: Larger Revolver

wjc - actually your point about the other two bolts\nuts not reinforcing the other side is probably more relevant, as that would also distribute the stress over a larger area. I'm surprised any design engineer thought this split design was a good idea. Guess they do it so it'll fit inside the box easier?

JoeMamma - that's a strange problem. I'd ask TH to send you a replacement set, no shipping charges. (even if you HAVE bought other gear).

WHAT the bleep is going on at the Great Plains plant on China?? Also, I'm no manufacturing engineer, but I'm not even sure how these types of errors happen? Is someone from another mfg co messing with the machine settings?? Still, no excuse for QA not to catch it. OR is QA aware and they're letting these problems out the door anyway, hoping few will complain??
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Old 01-28-2013, 08:41 AM
  #6391
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Default RE: Larger Revolver

From what we hear here is more than a few. God only knows how many more we haven't hear from
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Old 01-28-2013, 09:45 AM
  #6392
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Quote:
ORIGINAL: lopflyers

From what we hear here is more than a few. God only knows how many more we haven't hear from
It seems there are no less than four of us here complaining and of course I stated of one other that the guy is living with his as they are minor so that tells me that there are issues and folks just don't bother to tell GP. When I called Tower Hobbies they sort of acted like they had not heard of any issues. Yeah, right! Or maybe guys have not opened and look at their planes or bothered to call in any issues. When I buy an ARF, I no longer will leave it in the box without a careful inspection, once I am satisfied all is good-to-go then I will put the parts back in and then it can be saved for later.

My first 70 size Revolver was closed to perfect except for one of the elevator slots off a tad and the rear canopy gap and that was it. Wing pins were straight and the wings fit very nicely going on the wing tube and to the fuse. Plane flew and tracked beautifully. Being the second great GP ARF I have had I was impressed with GP planes. The reason I bought this one was because I missed that plane.

BTW, on the landing gear. What I did no my first revolver was to fit a small aluminum plate against the gear where it bolts on. I put the bolts through the plate and into the gear. Maybe this helped more than I realized as I never had any issues. I would always do this with split gear. To me it just makes sense as split gear don't have as much strength in the mount area.

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Old 01-28-2013, 10:11 AM
  #6393
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Just got off the phone with GP support. Spoke to a guy named Robert - very nice guy. He said just shoot him the photos and they would take a look. I told him to check out this thread as others are reporting issues and he said he would definitely do that.

I told him I would get him some photos as soon as I can and send them to airsupport@hobbico.com. If I get another set of wings I want to make sure they measure them and check the pins before sending them out. No use to get a set with the same issues.
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Old 01-28-2013, 11:20 AM
  #6394
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Default RE: Larger Revolver

Luchnia and other who have had the issue with the anti-rotation pins not aligning:

Is it clear that the AR pins are misplaced in the wing root, or is it possible that the index holes are incorrectly placed in the fuse? May be a small point, but if we can figure it out, it might help GP sort out the QC issues.
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Old 01-28-2013, 01:05 PM
  #6395
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Default RE: Larger Revolver

What I found on my second R70 was that the holes were drilled fine but on one wing the rotation pin was tilted such that it would not go in the hole in the fuselage. I had to file the end of the pin to allow it to fit the hole.

Bruce
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Old 01-28-2013, 01:59 PM
  #6396
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Old 01-28-2013, 02:00 PM
  #6397
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I just came back from flying mine. It is just perfect.
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Old 01-28-2013, 02:07 PM
  #6398
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Default RE: Larger Revolver

I've had that too, where the anti-rotation pins were not perfectly square. As stated you can file it down, or, possibly, grab it with a channellocks, rotate it (to break the glue) and re-epoxy it in, square this time.
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Old 01-28-2013, 02:46 PM
  #6399
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Default RE: Larger Revolver

I’m not sure what type problem some of you are having with the split gear. My gear also broke off from turning while taxiing. It was similar to the picture u2fletch posted. What little glue was on the LG block just did not hold. When the block pulled loose all that was holding the gear on was some small strips of 1/16 plywood, which easily broke. It was also easily repaired and epoxied back, so it won’t break in that particular place again.
Are there other problems with the gear? The gear itself is solidly attached to the plywood block even if the bolts are in a straight line. That will make no difference on whether the block comes off from lack of glue. If it is the plywood block that comes out every time, I can’t see what good reinforcing the gear with a plate joining the two halves, or changing the bolt pattern would do.
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Old 01-28-2013, 03:17 PM
  #6400
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Default RE: Larger Revolver

RoyR -

I see two major problems with the stock gear config. The split means that, unless you hit both wheels at exactly the same time, you're getting a lot of torque on one side, which is supported by only two bolts\nuts, instead of four. My gut says that that momentary stress increases the chance of failure of the supporting fuse area. This is magnified by what we have known for years now is an already weak LG area. This force is also increased when you have a rough landing or have the uneven stresses of a grass field.

The problem I see with in-line bolts is that the general force of a landing on the gear is not only straight up into the fuse, but also back. The length of the gear acts as a lever against those bolts\nuts, magnifying any longitudinal force. A box formation gives you longitidinal support to handle this stress - a line-formation does not. I have seen Revolver gear where only one side of the gear split out, and, in another instance, folded under. I have never seen a failure on my setup, despite some rough landings (and crashes!)

Could the stock gear formation hold if you keep reinforcing every time it fails? Probably, eventually. But I'd rather avoid all the pain and suspense and address this weakness up front. But that's just my preference from my experience.
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