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KMP 87" Yak-54 What do you Think?

Old 02-21-2005, 11:29 AM
  #126  
3dking
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Default RE: KMP 87" Yak-54 What do you Think?

You tore that plane up Mike.
Old 02-21-2005, 04:44 PM
  #127  
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Default RE: KMP 87" Yak-54 What do you Think?

Maud,

you think JR 8411 servos might have been too weak????

I have not measured the Dave Patrick horns i will measure my DuBro servo arms.,..

For three flights this thing 3D'ed well, I was High A KE and Harrier rolling it , Full Rate Ailerons were crisp and clean.

Oh, well. Motor box going together tonite. Then glass time.

If I had a 25mm tube it would fly this weekend.,

Question my tube is 920mm long , would it be ok to go shorter with a CF tube? I cant find a CF 25mm tube longer than 700.
Old 02-21-2005, 04:53 PM
  #128  
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Default RE: KMP 87" Yak-54 What do you Think?

I just got off the phone with KMP. He's going to look to see if he has a spare wing tube Mike. He will call me tomorrow and I will let you know.
Old 02-21-2005, 04:56 PM
  #129  
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Default RE: KMP 87" Yak-54 What do you Think?

www.troybuiltmodels.com
ORIGINAL: Bosshossv8

Anyone have a source for wing tube stock...CF or Alum???

Old 02-21-2005, 04:57 PM
  #130  
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Default RE: KMP 87" Yak-54 What do you Think?

http://www.rcuniverse.com/forum/upfi...28/Rm36795.jpg

If you would of used a regular bolt the wing wouldn't of rotated out.
Old 02-21-2005, 05:09 PM
  #131  
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Default RE: KMP 87" Yak-54 What do you Think?


Nope... the JR 8411's are just fine... I was commenting on the length of the servo arms (not the control horns)...

It looks like your servo arms were/are setup on the 1.5" mark... there's been some reports of 1.5 arms inducing flutter.... or at least contributing to the destruction caused by it.

I don't really understand it all, but have heard it enough that I stay away from it.

It is more likely that is a result of a minimum servo being used and the 1.5" arm reduces the effective torque of the servo... They are measured and rated at 1" from the output shaft center... 1.5" would reduce the torque significantly (due to leverage)unless the linkage/control horn was designed to match it.

Theoretically the best advantage is a 1:1 ratio... 1" from the center of the arm, 1" from the surface pivot point.

Some may have been setting the control horn short and the servo arm at 1.5"... this would give the surface a significant leverage advantage...


ORIGINAL: Bosshossv8

Maud,

you think JR 8411 servos might have been too weak????

I have not measured the Dave Patrick horns i will measure my DuBro servo arms.,..

For three flights this thing 3D'ed well, I was High A KE and Harrier rolling it , Full Rate Ailerons were crisp and clean.

Oh, well. Motor box going together tonite. Then glass time.

If I had a 25mm tube it would fly this weekend.,

Question my tube is 920mm long , would it be ok to go shorter with a CF tube? I cant find a CF 25mm tube longer than 700.
Old 02-21-2005, 05:29 PM
  #132  
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Default RE: KMP 87" Yak-54 What do you Think?

ORIGINAL: craZaboutplns

I just got off the phone with KMP. He's going to look to see if he has a spare wing tube Mike. He will call me tomorrow and I will let you know.
HaHa,

I just got off the phone with him too, before I read this post.

Cool,

It will fly again, and this time for keeps.

Maudib,

I will post my arm and horn setup.

motor box time.
Old 05-01-2005, 07:30 AM
  #133  
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Default RE: KMP 87" Yak-54 What do you Think?

Old 05-01-2005, 08:56 PM
  #134  
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Default RE: KMP 87" Yak-54 What do you Think?

my kmp yak is repaired from the crash...installing motor and servo...tank now on CG .

A LITTLE BEAT UP....but it will fly..got th ewing tube fron Andrew at KMP.
Old 06-28-2005, 01:19 PM
  #135  
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Default RE: KMP 87" Yak-54 What do you Think?

Boss,

Did the aileron hard point fail, or did the aileron horn fail? I'm glad you got the Yak ready to fly again. Good luck.

Dennis
Old 06-28-2005, 10:45 PM
  #136  
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Default RE: KMP 87" Yak-54 What do you Think?

The aileron horn was installed properly. It was not into the hard point. Only soft balsa[&:][&:][&:]

I nought it this way and trusted the installation , not checking to see if it was into the hard point.

My fault totally. If I had built the plane initially it would still be flying. I stopped work on it, only because of time . It will fly befor ethe season gets too much longer.


And I will post pictures and reports. From the three flights I had on her, it was an amazing ride. Absolutly a dream to fly.
Old 06-29-2005, 12:51 PM
  #137  
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Default RE: KMP 87" Yak-54 What do you Think?

For people interested in the wing tube strength I made some measurements, and assuming the grade of aluminum in the tube is correct(maybe a big assumption), it should be strong enough.

The tube is a 25mm(.9842) tube with a 2mm(.0787) wall thickness, which as stated should be fine if a good grade of aluminum was used. I have an old 1" tube from some plane from a few years back(I can't remember which one) and it has a wall thickness of .050, so the KMP one is significantly thicker, which is not conclusive as to its strength, but at least it isn't thinner.

More interesting facts. I thought the tube fit was a bit loose and I was right. The internal measurement of the composite housing tube is 1.002, leaving about .0177 clearance, which is a bit too sloppy in my book, but probably not a big problem....BUT, the interesting issue is that you may be able to find a very straight CF tube that is an accurate 1.000" inches and it may just fit in the existing mounting tube. My old 1" aluminum tube won't quite fit, but after measuring it that isn't a surprise since it varies from 1.000 to 1.0030, and it isn't oval, it just varies by that much. Even if you find a 1.000 tube, 2 thou may not be enough since the housing tube probably varies in size too, but it is worth a try. A little mix and match and we might be able to come up with a good CF option.

Maybe if anyone out there has a 1" CF tube and has the ability to measure it accurately, they can tell us what it is and there may be a good option available for the KMP owners out there. I'm going to write the couple of manufacturer's I know out there and see if they'll send accurate measurements to me.
Old 06-29-2005, 01:20 PM
  #138  
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Default RE: KMP 87" Yak-54 What do you Think?

Hey Bill

It's been a while.
Hope all is going well for you and look forward to hearing your thoughts on this Yak.
Old 06-29-2005, 02:04 PM
  #139  
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Default RE: KMP 87" Yak-54 What do you Think?

About 20 flights on mine and still going strong. This is a nice flying plane. There
were a few minor issues with mine that had to be corrected. If EF has any more
rejects, I wish they would please send them my way. Below is a link to a short video
that I posted a few weeks back. I'm using a ZDZ 50 for power, 5645s on all surfaces
except an 8611 on rudder. The ZDZ has been a really smooth running engine. The
first video is without music. The second one was put to music.

http://thedials.org/Pictures%20Greg/3Dvideo1.wmv

http://thedials.org/Pictures%20Greg/3Dvideo3.wmv

Greg
Old 06-29-2005, 03:43 PM
  #140  
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Default RE: KMP 87" Yak-54 What do you Think?

Hi Doug,

Great to see you're still stompn' around. It's nice to be back, and yes, it has been awhile. This plane ought to be extra fun because there's plenty to talk about.

Hey Greg,

Thanks for the feedback and the videos. Nice job on the videos and the flying. You make me wish that I had mine done. It looks like flies very well.
Old 06-30-2005, 07:20 AM
  #141  
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Default RE: KMP 87" Yak-54 What do you Think?

Hi,

I am downloading the videos now.

a word onthe wing tube issue.


During my crash...in slow motion...the wing tube bent. But this is after the wing came out just enough to get past the anti-rotation pins. The plane was already in a semi flat spin spiral. But we got to watch the tube bend in real time[X(][X(][X(] I actullay think it helped land the plane flat.[&:]


I have tried an EF Yak 87" tube. I own a couple of them. No Dice. Just a few thousandth's to big. It would not go into the wings at all...a little way into the fuse. It would be a lot of work to retrofit the phenolic tube for it.

But, PBG in Austrailia will make a 25mm 920mm long tube. for about 70 bucks.

I got lucky and got another from Andrew at KMP , the last one reportedly.

I am looking forward to flying this bird again, soon. I whave repaired the damage and will whip it around like a demon .

Everyone who saw this plane fly that fateful Sunday, said :

1== this is does not fly like a reject.

2 === It actulaly looks OK ...albeit from a distance.

3 == The bad rap this plane got was a little harsh.

4 == Where can I get one??

So, even though the history of this plane and it's associated business deals, it is still a very god plane, and a modeler with a little buildng experience can make it a great one.

I flew mine wityh a Quadra 52 ...it was awesome. I am going DA-50 on it the second time around. It flew that good, so I am putting the hot-rod in her.
Old 06-30-2005, 09:24 AM
  #142  
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Default RE: KMP 87" Yak-54 What do you Think?

Edit... Maybe you are right... I shouldn't have said anything...
Old 06-30-2005, 09:35 AM
  #143  
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Default RE: KMP 87" Yak-54 What do you Think?

Edited: Maybe you are right... I shouldn't have sadi anything...
Old 06-30-2005, 09:42 AM
  #144  
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Default RE: KMP 87" Yak-54 What do you Think?

Maudib,

Even though I'm sure your intentions must be good, I really can see no point in your post to this thread. Hopefully people posting here will have seen, flown, owned, built or are interested in the KMP YAK and will be adding something positive to help people trying to get their KMP YAKs flying. It serves no positive purpose to gloat, talk down to, or basically be unjustifiably negative about this plane. Since you have an EF YAK, that's great, but it seems your energies would be more positively spent posting in the EF YAK build and fly forum.

Please stop trying to disrupt this thread, it serves a very positive purpose for us lowly KMP YAK owners, and we don't need to listen to you pontificating with totally valueless, negative input.

I will be asking the moderators to remove yours and my post to help stop this negative spin.

Can the negative posting by EF owners to this thread please stop at this post.

Thank you for respecting our thread.

Old 06-30-2005, 09:56 AM
  #145  
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Default RE: KMP 87" Yak-54 What do you Think?

Edited: Maybe you are right... I shouldn't have said anything...

I was just curious as to what changed BossHoss's view of the plane, as his first assessment seemed pretty down on the plane, and now it's not so bad afterall...

Perhaps if he can clarify that, many will understand that his initial assessment was hasty and that indeed these planes are not deserving of as bad a rep as they got.

It seems several of you are flying and enjoying this plane... I didn't mean to take anything from that...
Old 06-30-2005, 09:59 AM
  #146  
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Default RE: KMP 87" Yak-54 What do you Think?

Well put Bill.

I think you are correct, RCU is full of gloaters, and people trying to one up each other. I want to open the KMP Yak thread and read about putting this Yak together, and flying tips, etc... I don't want to read about how EF is the greatest thing since moon pies... My DA is bigger than your Brison.... I did the same in the EF Yak thread, lots of good info... but you still had the " I have more than you " crowd buzzing around that thread.

I have EF, and wildhare models flying now. I love them, and frankly, they are awesome. But I wanted to give this bird a try, I'll have about $600 in the airframe and engine. I'm going to go with Columbo's servo setup (4 5645's, and a 8611 on rudder) that will be about $270 more... Hopefully, I can work around some of the quirky stuff when putting this thing together, and it will be a great flyer... From the video posted by Columbo, it looks light, and looks very stable.
Old 06-30-2005, 10:13 AM
  #147  
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Default RE: KMP 87" Yak-54 What do you Think?

Maudib,

Thank you for taking my comments in the right spirit. I believe it has been quite clear in this thread, and others, that this plane is basically a liquidation plane. I think the implications of that are quite clear to everyone. Let us not forget that before there were ARFs, there were kits. Anything that needs replacing on this plane can be done without just ordering a replacement part(Bosshossv8 has shown that). Again, this plane is not for everyone, but I think the people buying them deserve being respected for their decisions and not be treated like they're of lesser..uhhh...intelligence(?) than someone that bought a EF or other "brand name" YAK.

Now back to the topic of this thread.

frieshoo:

I'm with you. I'm going to try and do this whole project as cheaply as possible. In fact, because the plane only cost me $300 and there's not much to lose, I'm going to be taking a bit of chance with some of the equipment trying to bring this bird in cheap. I'm almost embarassed to admit this(but I think it will be a fun experiment) but I just bought 4 XPower(what the h... are those?) S9350 for $20 each off of eBay for the elevators and ailerons. I haven't decided on a rudder servo yet, but I'll probably have to go with a good one there.

BTW, I meant to mention that the XPower servos are about 150 in/oz and .17 transit at 6v analog servos. Should be enough, but not the fastest in the world, though in my experience, the average flyer cannot tell the difference between a .17 transit and a .13 transit, as with the 5945, and I have no plans of doing any contest work so I'm sure they'll be fast enough....I'll just have to think .04 seconds more ahead of the plane.
Old 06-30-2005, 11:57 AM
  #148  
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Default RE: KMP 87" Yak-54 What do you Think?

First,

I respect J. David and anything he posts. I did not see the negative comments if there were any.

What changed my mind....time. And 3 flights.


DO NOT USE 5645 servos they will make you hate the plane. Centering is terrible and they are sloppy. Spend the money on 5945's.

If you got this plane cheap, like I did, you want to keep it cheap. But, here is the rub. It will fly like whatever you put in it. Garbage in ...garbage out.

This plane has the potential to fly every bit as good as an EF Yak. I have both, fly both , and know this for a fact. Yup, the KMP was poorly constructed by some standards. Fix it, beef it, and build it right and if you could fly it color blind you wouldn;t know the difference.

This is one bargain plane that you can make into a TOC contender. I will be flamed by the loyal EF guys, of which I am a part of, but, I am telling the truth. And sometimes the truth hurts.

But I have the right to speak my mind, I have spent a LOT of money on these Yak's and am willing to tell my experiences without holding punches.

How many Yak's do you all own??? I own 11. The KMP is just one of them .
Old 06-30-2005, 12:11 PM
  #149  
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Default RE: KMP 87" Yak-54 What do you Think?

Boss, your honesty is appreciated.
Old 06-30-2005, 03:44 PM
  #150  
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Default RE: KMP 87" Yak-54 What do you Think?

Hi Bosshossv8,

You are obviously welcome to your interpretation of your friend's remarks, but some of us see them in a different light. We'll just have to disagree on that one.

I'm not sure who you're aiming your "But I have the right to speak my mind" remarks to, since I haven't seen anyone questioning your input, except by inference perhaps your friend you're defending, but I for one very much appreciate your input, since with your experience with both brand YAKs makes your opinion bare the most weight of anyone that has posted here.

>>Garbage in ...garbage out.

What is "garbage" is obvious very subjective. One person's garbage is another person's treasure. Of course, typically the more expensive the servo the better it is going to be, but how much servo do you need for sport flying? If you're doing contest flying, sure, spend the bucks and get the best, but for the average flyer(95% of us?) I could put two identical planes up, one with 5645's and one with 5945's and it's unlikely any of that 95% would be able to tell the difference. Of course, if there was something wrong with one of the servos and it wasn't centering to spec then it would be very noticeable. If 5645's fail often and don't operate to spec, then I wouldn't want them either. Maybe when I get my plane done with my "garbage" servos, I'll take a video and you can tell me(I trust your honesty) if you can tell I have cheap servos in it. If you think servos such as the 5645's, and the even cheaper analog servos I'm going to try, are so awful you'll be able to tell the difference looking at the plane fly. Most of the overwhelming use of digitals in our giants is due to marketing hype, not need. It has only be a couple of years since 9402's were the hot thing for 40%er's and I didn't see any planes falling out of the sky because of them(you can't say that about the digitals), and they seemed to fly pretty well at the highest level too. Of course there are advantages now to the high torque and precision digitals offer for contest performance, but I am still not convinced that their reliability has matched the good old analogs.

>>But I have the right to speak my mind, I have spent a LOT of money on these Yak's and am willing to tell my experiences without holding punches.

Please don't let the KMP bashers slow you down, just keep it coming. Your honest feedback is very welcome.

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