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Ultra RC 87" Yak Build and Fly

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Ultra RC 87" Yak Build and Fly

Old 12-01-2006, 09:24 AM
  #101  
RC_DESI
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Default RE: Ultra RC 87" Yak Build and Fly

VFalcon7, Noticed that the RX batteries are pretty close to the Motor.

Do'nt u think that'll cause interference (recommended distance is 10-12 inches etc) ?

I have a Pitts Muffler for my DA50 & guess will need to buy a heavier (Dave Brown) spinner to balance it.
Old 12-01-2006, 09:29 AM
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Default RE: Ultra RC 87" Yak Build and Fly

Guys I have a small issue with the covering.

I am NOT able to get it tight. I use the sealing iron/heat gun & tighten/shrink it up, but after 1-2 days the wrinkles reappear. Is this cos of the cold weather/humidity in wood etc? any ideas?
Old 12-01-2006, 09:38 AM
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Default RE: Ultra RC 87" Yak Build and Fly

Sometimes it does take a few passes to get it shrunk. It's Ultracoate and IMO has the best shrink/retention of them all. Still when being covered they sometimes leave a little too much slack... shrinks up under heat but over time sags again.

Again... over time it will eventually shink up and hold well. And yes... your airframe is probably pretty "wet" right now. I did a Lanier Yak and it lost nealry 1/4 lb in water weight just sitting in the shop... no lie. THis shrnkage will indeed add to the covering sag.

Don't go overboard in shrinking it... just taught it up... and before your ready to fly... it'll get there (or should).

Where is your's loose? Mine is drum taught on all three except maybe for a bay or two under the tail where the stringers are... (these too will bend and dry letting the covering sag again... that' why I recommend you just taught it and leave it til the airframe is "cured".
Old 12-01-2006, 10:43 AM
  #104  
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Default RE: Ultra RC 87" Yak Build and Fly

Arvind, I have had this same set up in 2 other yaks so far and I have had no problems... I also talked to Da and you are right that is what they recommend. They also said if I am not experiencing any problems then go ahead fly that way. So I do not know, this is how my plane balanced out with the tuned pipe so I am living with it.

I do have the stock and large Jtech that I could switch to if I do not like how it flys. I figured that my set up is the same as Extreme Flights 87" in that they used the tuned pipe with everything up front???(no smoke in theres) I'll give it a go and report back.
Old 12-01-2006, 10:52 AM
  #105  
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Default RE: Ultra RC 87" Yak Build and Fly


ORIGINAL: vfalcon7

Thanks. Weather di not cooperate today and ofcourse rain tomorrow... The CG came out at 6 3/4 with everything up front minus one reg and the receiver. sent some pics
How did you secure your pipe in the rear? I used the same setup. I flew mine last week, sick power!
Old 12-01-2006, 11:03 AM
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Default RE: Ultra RC 87" Yak Build and Fly

ORIGINAL: Maudib

Where is your's loose? Mine is drum taught on all three except maybe for a bay or two under the tail where the stringers are... (these too will bend and dry letting the covering sag again... that' why I recommend you just taught it and leave it til the airframe is "cured".
The trailing edges of my elevators stabs are showing up wrinkles again & again. As I need that tight b4 I start gluing the hinges I cannot procced with that ;-)

Quick question (I do'nt have the manual yet)? What glue are u using for the Hinges?

I bought Pacer Hinge Glue (this will be first time I'll be using that, have used Gorilla Glue for Robart hinge points previously). Do I need to apply vaseline/oil on the Hinge points/axle for using Pacer glue too? OR does any overspill peel/come off the Hinge nylon easily later?

How long do u think I shd let the airframe sit in the house to let it dry up 1-2 weeks?

--Arvind
Old 12-01-2006, 11:05 AM
  #107  
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Default RE: Ultra RC 87" Yak Build and Fly

As far as the stab tube alignment. I found when I had the tubes in they were slightly off, but when I screwed the stab tight to the fuse it looks straight to the wing tube.

My wing had a big twist in it that made the maiden flight horrible. The wing root was at 0 incedence and the wing tip was plus 3 on the right side and -1 on the left side. This was a very easy fix, just twist the wing by hand and shrink the covering back to hold it in place. It took two tries to get Zero incedence. About 15 minutes of work.

I am taking it back out tomorrow to try again.
Old 12-01-2006, 11:51 AM
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Default RE: Ultra RC 87" Yak Build and Fly

If you're talking about the bevels where covering is on covering?... not sure you'll get many additional wrinkles out after a good hot ironing... thought you were talking about open bays... how about a pic of what you are concerned about?

I've not used Pacer Hingeglue... I'll be using eopxy I think... maybe someone else can chime in here...

As far as "drying" the airframe... you don't really need to... this will actually change from time of year to time of year... on any airframe... the moisture content... it was a suggestion for those that might be getting a little twist/wrinkling due to it.

Just a couple days in a climate controlled workshop will stabilize the moisture content... no need to hold off building for that.
Old 12-01-2006, 11:58 AM
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Default RE: Ultra RC 87" Yak Build and Fly

My tubes are dead nuts in allignment. Very nice. Covering is very good, hardley any loose spots.

I agree to go easy on the heat gun or you will twist things.

Pacer is the THE best hinge glue IMO. I used it the last 50cc gasser I did and I will never use anything else ever again. It's strong as hell. The manual says to use Lithium grease on the hinge pins to keep them free of glue. If they bind after they are dry they say to use ONE drop of acetone on the pin. Then after it works free apply ONE drop of oil on the pin. No more than one drop.
Old 12-01-2006, 06:53 PM
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Default RE: Ultra RC 87" Yak Build and Fly

Maudib
you know i was racking my brain trying to think of the easy way to fix,i think i will give it a try i am going nuts waiting for the new fuse to show,can't do much more till that shows.
THANKS FOR THE IDEA! it's not off a hole lot just don't want to fly it that way.
ENJOY!
Old 12-01-2006, 08:37 PM
  #111  
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Default RE: Ultra RC 87" Yak Build and Fly

Hey guys,

My Yak arrived today. I got a quick look at it and noticed a couple of thing I am curious about.


The hinges have what looks like just pieces of wire for the hinge pin and their is quit a bit of play in the hinges.It looks like they need to have larger diameter pins .
The paint on the cowling and the canopy look very good but , the shade of red does not exactly match the red covering.
Are these things that the rest of you are seeing with yours ?
I am going to call Ultra RC about the hinges.
Otherwise everything looks real good. I have not had time to check the wing and stab. tube alignment yet.



Rick
Old 12-01-2006, 09:22 PM
  #112  
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Default RE: Ultra RC 87" Yak Build and Fly

The hinges have the least little play (or at least mine do) perhaps .001" Nothing to be concerned about at all...

My cowl matches pretty close... but the Oracover(Ultracote) varies batch by batch... and yours could be the slightest shade one way or another... nearly impossible to mass produce cowls that match a covering that varies slightly over bacthes....
Old 12-02-2006, 10:22 AM
  #113  
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Default RE: Ultra RC 87" Yak Build and Fly

Rick,

I had the same concerns as you & as I'm picky about details, I bought some Steel Music wire (think 0.039" ) from the hobby store & replaced all the pins. Took 15-20 mins

I modified it a lil just to make sure that they will NEVER slide out etc. The sides with the bend go inside the slots (inside the fixed surface) & when glued in will never move laterally etc.

--Arvind

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Old 12-02-2006, 10:55 AM
  #114  
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Default RE: Ultra RC 87" Yak Build and Fly

I use one piece of piano wire for the entire surface. It helps seal the gap and it the part is removable. On this plane I only did it to the rudder. I have been using this method on my 40% planes for years, it works well.
Old 12-02-2006, 12:52 PM
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Default RE: Ultra RC 87" Yak Build and Fly

Are you guys using the CF servo arms that came with the kit or using aluminum ones like SWB or Airwild? Thing is you have to buy the aluminum servo wheels anyway, how much more is it to just buy the complete SWB/Airwild arm? Are the complete arms any heavier?
Old 12-02-2006, 01:13 PM
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Default RE: Ultra RC 87" Yak Build and Fly

ORIGINAL: quist

I use one piece of piano wire for the entire surface. It helps seal the gap and it the part is removable. On this plane I only did it to the rudder. I have been using this method on my 40% planes for years, it works well.
I have started doing the same on the Rudders on my planes (make it removable is needed if u decide to sell the plane :-)
Old 12-02-2006, 01:19 PM
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Default RE: Ultra RC 87" Yak Build and Fly

Anyone know the Ultracote colors used for the plane? Also does anyone have a small piece of the Red, Yellow, Blue that they want to sell/spare? I have white ultracote. (to seal hinges etc)

Also was thinking if I can get 3 (other) people interested, I can buy the 4 colors & we can split up the cost (I'll send 1/4 roll of each color to the 3 others). That way we all will have the 4 colors for the price of 1 roll. I do'nt want to spend the money for 4 rolls especially when I will not need the complete rolls. Just for patch work.

Let me know what u guys think...

--Arvind
Old 12-02-2006, 01:25 PM
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Default RE: Ultra RC 87" Yak Build and Fly

I was just gonna use the Hitec SWB arms, I already have for the Elevators + Ailerons (5945's). Might get a Uni-Hub for the Rudder (8611) Or use the 3" arm I already have.

On second thoughts I'll use the 3" arm I have as if we have to Cross the pull-pull cables, then will rub against each other. With the 3" you can put 1 ball link on top & 1 on bottom to avoid that.

If you are using Hitec digitals, then I think using the Black Disk for creating the unihub/disk shd work if u do not have the Aluminium arms. I think using the CF horms will be heavier as you also have to use nuts + bolts (although the weight diff is gonna be marginal.)

--Arvind
Old 12-02-2006, 11:57 PM
  #119  
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Default RE: Ultra RC 87" Yak Build and Fly

ORIGINAL: arvind_rao

I was just gonna use the Hitec SWB arms, I already have for the Elevators + Ailerons (5945's). Might get a Uni-Hub for the Rudder (8611) Or use the 3" arm I already have.

On second thoughts I'll use the 3" arm I have as if we have to Cross the pull-pull cables, then will rub against each other. With the 3" you can put 1 ball link on top & 1 on bottom to avoid that.

If you are using Hitec digitals, then I think using the Black Disk for creating the unihub/disk shd work if u do not have the Aluminium arms. I think using the CF horms will be heavier as you also have to use nuts + bolts (although the weight diff is gonna be marginal.)

--Arvind
If you don't cross the pull pull wires, you will have to cut the exit slots in the side of the fus. much longer. I'm not so sure that makes things any stornger.
. john
Old 12-03-2006, 12:42 AM
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Default RE: Ultra RC 87" Yak Build and Fly

So if are crossing then we need an offset servo arm right? See example B of the link below.

http://www.swbmfg.com/rudex.html
Old 12-03-2006, 02:29 AM
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Default RE: Ultra RC 87" Yak Build and Fly

Yes you need an offset arm for a cross over, it is also slightly narrower. My Comp Arf 3 meter Extra 260 is setup with an Airwild servo tray for cross over cables, it is 4.86" instead of 5" wide and it is offset to the rear 5/16" and the cables also stay very tight.

The fuse is cut to accomodate an inline pull pull setup or crossover.

Edited for correct info[&:]
Old 12-03-2006, 08:50 AM
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Default RE: Ultra RC 87" Yak Build and Fly

Manual is now online at http://www.ultra-rc.com/50ccyak
Just under the "add to cart" button

The supplied rudder servo arm assembly is indeed offset and it shows the wires crossed. On my other Yak I used an Airwild Unihub to build this assembly and stayed stock. Worked great.

I replaced all the other servos arms with equivilent Airwild length aluminum arms. Many used the servi-supplied nylon disc without incident... but I just found it easier to order the extra aluminum arms from Airwild.

I also swapped out the supplied cableset with a Dubro set, as I wasn't completely satisfied with my ability to secure teh pull-pull wires in the hexends supplied... (slide cable thruough, bend over, push back in, and "lock in with set screw) SOme soldered the end of the bendover and that may be the ticket to using the stock hexends...
Old 12-03-2006, 10:11 AM
  #123  
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Default RE: Ultra RC 87" Yak Build and Fly

Arvind,

Good idea on the hinges . I think I will copy your idea. The hinges as they are have .020 or more slop in them, unacceptable.


THANKS,

Rick
Old 12-03-2006, 11:03 AM
  #124  
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Default RE: Ultra RC 87" Yak Build and Fly

SOunds like they did use a thinner wire on yours than mine... (whoever manufacturered the hinges that is)

Another option is to simply order Klett or DuBro pinned hinges. jtecrc.com use to carry them... (not on website but call)

I've had a chance to check both my hinge alignment and stab/wingtube alignment.

Unfortunately... the 4 center hinges on each wing are off as shared by others and my tubes are off by just a little.

When I get to it, I'll share the quick steps to correcting.

On the hinges... I have two options... either use the GP hinge slot tool to adjust the slots in the aileron to match the wing...

OR use hingepoints... I will probably lean towards the hingepoints... there seems to be plenty material for them to work and with Gorilla glue will "button" behind the surface nicely. I may keep the two end flat hinges since they are already aligned...

While this certainly SHOULD be unecessary in an ARF... it's not the end of the world nor a sign of QC... simply a mistake not caught early enough. I'm sure these things will be addressed in future builds.

The slight twist was prevalent in some of the EF releases (incuding mine) and was realigned very easily.

Outside of these two things... I can find nothing else but near perfection... I'm really looking forward to getting this together!

More to come...
Old 12-03-2006, 11:37 AM
  #125  
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Default RE: Ultra RC 87" Yak Build and Fly

I used the Hinge slot tool on my ailerons. It is a very fast fix.

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