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Help with building a GP Big Stik 40 w/ OS .55 AX

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Old 10-26-2008, 07:54 PM
  #26  
w8ye
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Default RE: Help with building a GP Big Stik 40 w/ OS .55 AX

Your parameters of control are that the closer for the main wheels to the center of gravity (yet in front of), the easier the tail dragger lands up to the point that nose overs become a problem.

With the center line of the wheels out in front of the leading edge of the wings, anything short a "full stall touch down" will bounce the plane back up into the air.

Due to the construction of the airplane we must often reach a compromise.

Almost all model airplanes have a bulkhead or former (usually F-2) at the leading edge of the wing. Therefore if using a fuselage mounted gear on a high wing plane, the aluminum gear is typically mounted right behind F-2. The straight side of the gear is mounted on the front side towards the former F-2. With a low wing plane, the wing is in the way so if you use a fuselage mounted gear on a low wing plane, you will locate the gear just in front of F-2 with the straight side of the gear towards the rear. Both planes perform satisfactory.

With wing mounted tail dragger main gear, Due the strength considerations, the mounting point must be just in front of the main spar. Therefore the gear legs must go forward from this point towards the leading edge so the plane will not nose over in practice. Take not of the Slow Poke or Astro Hog as a tail dragger. These two typically have the front of the tire at the leading edge. These two planes are usually on the tippy side if made like the plans.

I must add at this point about wheel alignment. First of all to have the gear mounted square is understood. Second the wheels need to be exactly square or to error on "toe-in" of the wheels. To have any "toe-out" will make the plane a "wild Thing".

On the tail wheel, the farther back from the pivot point of the tail wheel assembly is the wheel, the more sensitive and hard to control the plane will be. It has always worked well for me to have the pivot point of the tail wheel assembly to be at the rudder hinge line or more rearward. The wheel itself is always at least to the rear of the hinge line.

Life is but a compromise.
Old 10-26-2008, 08:29 PM
  #27  
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Default RE: Help with building a GP Big Stik 40 w/ OS .55 AX


ORIGINAL: fishingships

I do have a couple of more questions, however;

1) Since I am moving the main landing gear to the front of the plane to transform the Big Stik into a tail-dragger, do you think it is necessary to remove the mounting platform from the original location. I was planning on using my own (new) hardware and plywood support/platform. I just am wondering how many of you guys out there remove the (what will be ) unused hardware and plywood, etc. so that it is not adding to the weight of the plane, or am I just being anal here? I could, obviously reuse the included platform and blind-nuts but I am not too sure that would be best practice and would be of the structural integrity required for the fuse/landing gear.

2) To mount the tail-wheel to the fuse/stab I have a situation I do not know what to do with... please advise What I mean is, on the underside of the stabilizer, at the furthermost rearward part of the plane, the instructions call for mounting an included piece of balsa wood, called a "small ventral fin" It can be seen in this pdf manual on page 9 ( http://manuals.hobbico.com/gpm/gpma1220-1221-manual.pdf ).
The fin is approx. 6 inch. long and at it's tallest point, about 1 3/8 inch. and is 1/4 thick. It is a triangle, with the tallest end to be mounted to the rearmost part of the stabilizer. Being only 1/4 thick, either of the two tail-wheel assemblies I plan on using may be too wide. I am also concerned with the structural integrity of the ventral fin (and stab) upon landing, since the plane (ventral fin) was not designed for this application...??? Would you mount the tail-wheel assembly to the furthermost rearward section of the fuse, in front of the stabilizer instead, to resolve this issue? If so, would that be a problem in landing the aircraft?

The two tail-wheel mounting assemblies I will be choosing from (only because I already own them... I do not have any preference for ANY particular assembly) are:

Choice #1 http://www3.towerhobbies.com/cgi-bin...&I=LXFV47&P=ML
or Choice #2 http://www3.towerhobbies.com/cgi-bin...?&I=LXRWW8&P=7

I am not sure what is the best method to attach either of these 2 tail-wheel assemblies to the ventral fin??? Also, which tail-wheel assembly do you advise me to use, or please advise on a different one?

Your help is greatly appreciated.

Thanks so much.

Don
The landing gear assemblies you have on hand are very nice ones and I have several planes with the Sullivan style and a couple with the Dubro (old Klett design) tail wheel.
However, they do not lend themselves to installation on a model like the big stick handily. I used this Dubro style as this:

http://www3.towerhobbies.com/cgi-bin...&I=LXD850&P=ML

To avoid using a separate push rod to the tail wheel assembly, I have always hooked the tail wheel steering directly into the rudder with a 90 degree turn of the tail wheel steering wire.

With your assemblies you have on hand and considering the rudder design of your plane, you will need a more or less "jack shaft" to extend below your fuselage with a belcrank on its end to be able to hook up steering control on your plane.

I horse traded for a tail dragger Big Stick one time where the guy never installed the ventral fin you have referred to. I had seen the plane fly many times and it performed OK without the ventral fin. However I made a ventral fin from scratch wide enough for a tail wheel backet to mount. The plane flew a normal life span.

You could get by without a purchased tail wheel assembly. Just use the previously mentioned brass tubing itself as your tail wheel bracket. Use 1/16 piano wire to go up into the rudder. Have the tubing and the wire extend down through your ventral fin and turn out to the rear with your wheel mounted. In the previous picture of the LT40 tail wheel, the Dubro bracket is actually redundant unnecessary support.

Jim
Old 10-26-2008, 11:20 PM
  #28  
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Default RE: Help with building a GP Big Stik 40 w/ OS .55 AX

Hi fish,
You are getting good help so far, so hopefully I won't mess it up.

Leave the original gear block where it is, hopefully they just covered over it at the factory and you don't have to do anything in this area.
Besides the plane is reportedly nose heavy so you need the weight behind the CG anyway.

Do not use the little fin if you are going to use a tail wheel.
Instead of the fin cut yourself a piece of aircraft ply (I would use 1/8" ) that matches the shape of the bottom of the fuselage in the same area where it says to mount the fin.
Make this plywood long enough for the tail wheel assembly to mount to.
I would install blind nuts in the plywood for the tail wheel to bolt into, remove the covering on the bottom to match the plywood and epoxy it into place.
This will give you a very strong tailwheel mounting plate.
The Dubro would be my choice because it uses a control arm, the Sullivan needs to be attached to the rudder which is not really accessible on this plane.
Just run another push rod to operate the tail wheel that is attached to the rudder push rod with wheel collars.
If you need more description on how to do this, I or someone else can give directions.

................................................ed it here ........................................
I just saw what W8ye posted about the tail wheel, obviously we would go in different directions but the way he has described is a good way to do it too.
Old 10-26-2008, 11:25 PM
  #29  
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Default RE: Help with building a GP Big Stik 40 w/ OS .55 AX

Charlie has good advice.

Those mounting old blocks will cause more trouble to remove than to just leave them in the plane
Old 10-27-2008, 07:58 AM
  #30  
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Default RE: Help with building a GP Big Stik 40 w/ OS .55 AX


ORIGINAL: fishingships

Damn Dignlvn, that is one AWESOME lookin' plane.. truly congrats and a great looking build... fine job !

Now, I am back to the GP.. ahhh... all's it takes is a reminder of what we already have (at least possibly in my case) !

Thank you so much for your pic's.. they're wonderful..

A couple of quick questions though:
1. What is the round device that sits atop the wing?? Looks like a compass from this perspective, but I doubt that would be it
2. Where did you get your landing gear setup? Mfr., et al.?
3. My LHS guy told me that making it a taildragger (with a GP Stik) is problematic because of the rudder does not fully extend downward... he said it would have to be a "floating" rear wheel setup. Yours?

Again, beautiful work and beautiful plane...

Peace be with you.

Don


Don

Thanks for your kind words, i'll try to answer some of your
questions.

1. The round device is just a Switch compartment with a lid.
I was breaking in the Saito and the excess fuel mess was getting
on the Switch. So I inclosed it. (like a plastic Petrie dish)

2. Carrell answered this one already, with links too.

3. I used a Ohio superstar Tailwheel assembly and an extra
Servo to control the the T/W.

http://www3.towerhobbies.com/cgi-bin...&I=LXBN38&P=SM

Hope this helps,

Bob
Old 12-10-2008, 11:45 PM
  #31  
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Default RE: Help with building a GP Big Stik 40 w/ OS .55 AX

Hey dig !

Just a quick question or two on your beautiful GP Big Stik...

1. Is it a 40 or 60 size? (looks like a 60?)
2. What engine do you have mounted, looks like a Saito, but what size?

I am building both the 40 and the 60... and I am planning on the OS .55AX for the 40 and probably the Saito 91 Golden Knight AAC or 100 Golden Knight AAC on the 60 size ARF. Your thoughts?


Thanks,

Don
Old 12-11-2008, 08:33 AM
  #32  
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Default RE: Help with building a GP Big Stik 40 w/ OS .55 AX




Hey Don,


I have the 40 size Stik with a Saito 82 using
Futaba 2.4 radio. I'm partial to 4 strokes myself.

Bob
Old 12-11-2008, 09:22 AM
  #33  
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Default RE: Help with building a GP Big Stik 40 w/ OS .55 AX

My Big Stik 60 came out nose heavy with an OS 91 four stroke. We put the battery pack as far behind the wing as we could without cutting a hole in the fuselage, and still had to add around an ounce of lead to the bottom of the stabilizer.

The Saito four strokes are slightly lighter than the OS, and every model varies slightly, so you may not have this issue.
Old 12-11-2008, 05:43 PM
  #34  
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Default RE: Help with building a GP Big Stik 40 w/ OS .55 AX

Hey guys !

Thanks for getting back to me...

My preference ( the black will look excellent w/ the Stik!) http://www.horizonhobby.com/Products...dID=SAIE125AGK

So, is this too much engine? or too heavy?? What are your thoughts? I also would like to go with a 4-stroke, so if the engine above is too much or too heavy, I have the 100 to go down to, or back to a 2-stroke OS (which is not a problem 'cause I do love OS AX engines).... (the Saito 1.25 is lower weight (overall) than the OS 120 AX) Also, the OS 75 AX is a popular choice for the Big Stik 60, but for eventual 3D, not sure.


Note: I would eventually like to get this bird to do some 3D... as I get able to do so...

... just let me know your thoughts and positives vs. negatives or alternatives... I will be forever grateful..

Thanks so much for your help and opinions... they are valued.

Peace.

Don
Old 12-11-2008, 08:32 PM
  #35  
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Default RE: Help with building a GP Big Stik 40 w/ OS .55 AX

In my opinion the Saito 125 is not to much engine for the Big Stick 60.
Even though the 125 will pull it straight up without breathing hard there is more to doing 3d than excessive power.
The Big Stick is not a 3d capable airplane.
I really like the Big Stick and think it is a really great sport plane that is a lot of fun to twist into knots, but when it comes to precision flying it does not even knife edge very well if at all.
Compared to 3d planes it is heavy, has a narrow fuselage, small control surfaces, and a big fat symetrical airfoil.
So in the interest of you not being disappointed ....... if you intend to 3d buy a different airplane.
Old 12-11-2008, 08:56 PM
  #36  
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Default RE: Help with building a GP Big Stik 40 w/ OS .55 AX

The Twist 60 with the Saito 125 is a little more 3D capable though I'm sure there are more capable planes
Old 12-12-2008, 01:13 AM
  #37  
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Default RE: Help with building a GP Big Stik 40 w/ OS .55 AX

Chashint,

I totally agree with you on all points... I just wanted to try the Stik at 3D and thought that the 125 Saito would give me enough pull... I just bought a new assembled Seagull Ultimate 90 for short money from a friend and am hoping it will be another stepping stone towards 3D. I bought both the GP Big Stik 60 and the Seagull from the same friend and both were extremely inexpensive, so my thoughts are that they can be my trial and error planes, while I learn, even though, as you so rightly point out, the Stik is not a 3D plane. I do expect, as you mention, to have a load of fun with it, as most people seem to enjoy it's flight characteristics. I appreciate your opinion and viewpoint, they are valued, as all others who have posted.

You do believe that the 125 Saito is not too much power, though and I would appreciate any or more of your thoughts on whether you believe it is a good choice, or should I stick with a smaller engine and use the Big Stik as you mention, and how it was designed, an aerobatic/sport plane? Thank you in advance for your feedback.

Peace.

Don

Here is the Ultimate I just bought used/never flown/assembled: http://www.horizonhobby.com/Products...ProdID=SEA5050

Let me know what you think of the Ultimate and a 125 or even a 150 Saito in the front???
Old 12-12-2008, 07:19 PM
  #38  
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Default RE: Help with building a GP Big Stik 40 w/ OS .55 AX

I'd put the 100 on the 60 size Stik. You already have it. It is plenty of power, it weighs about the same as a 91.



You should start a new thread to get recommendations for the Ultimate. People who are into 3D biplanes may not read a Stik thread. The 125 is physically about the same size as the 91 and 100. Weight is also similar. The Saito 150 is externally much bigger, and is heavier, than the 125.
Old 12-12-2008, 08:45 PM
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Default RE: Help with building a GP Big Stik 40 w/ OS .55 AX

It will be a good combination
Old 12-12-2008, 10:19 PM
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Default RE: Help with building a GP Big Stik 40 w/ OS .55 AX

I agree with both of you guys, Carrellh and w8ye.. I just looked at the 100, and that is prolly going to be the play on the Stik 60... nice engine, and will look nice w/ the black/gold on the Stik... I hate to spend the extra money for just the black and gold but it should look great, and they are the colors of my favorite team... Boston Bruins !

Thanks guys, you all have been so very helpful... great people in these threads... thank God for the USA !

Peace.

Don
Old 12-12-2008, 11:55 PM
  #41  
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Default RE: Help with building a GP Big Stik 40 w/ OS .55 AX

MY FRIEND
K
I HAVE A BIG STIK 60, 40 AND ULTRA STIK 60 AND 40. ULTRA STIK ARE FAR BETTER BUT MY LITTER GP .40 STIK INITALLY I TRIED A SAITO .72 BUT IT WAS TOO HEAVY. AND I HAVE GONE TO A .46 MAGNUM WITH AN OS CARB AND A TOWER MUFFLERS AND ITS A ROCKET SHIP. I'VE GOTTA USE A 12X7 PROP TO SLOW THE ENGINE DOWN BUT THE PLANE HAS BEEN MODIFIED TO TAIL DRAGGER I HAVE A HAYES TANK WHICH IS THE BEST AND LEAKS OR SPLITS LESS THAN ALL THE OTHERS I'VE TRIED. I'VE FIBERGLASS THE FUSE WHERE THE RUNNING GEAR MOUNTS AND THERE IS NO NO NO DIHEADRAL IN NONE OF MY STIK WINGS. IT DOES A CLEAN SWEET KNIFE EDGE BUT NO FLAT SPINS BECAUSE OF TAIL SECTION. MY GOAL WAS TO KEEP IT LIGHT WITH OPITMUM POWER. I RUN HITEC 475 KARBONITE GEAR SERVOS ON ALL SURFACES. PLANE FLYS GREAT SURPRISINGLY WITH THE MAGNUM. I WON THE PLANE AT A CLUB RAFFLE IS THE ONLY REASON I HAVE IT. IF YOU CAN GET THE HANGER 9 ULTRA STIK WITH THE OS .55 AND ULTRA THRUST MUFFLER FROM PERFORMANCE SPECIALTIES, WHEN I FLY IT PEOPLE WATCH, IT WILL DO EVERYTHING AND ITS EXTREMELY FAST !!!1!!!!!!

FAST EDDIE
Old 12-14-2008, 02:14 PM
  #42  
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Default RE: Help with building a GP Big Stik 40 w/ OS .55 AX

Hi Don,
How many Saitos do you have just sitting around ??
You could make a case for any of these engines 82, 91, 100, 115, or even 125.
I know its only $30 extra for the Golden Knight .......... but if it were me and I was deciding between the 1.00 with bling or the 1.15 without bling I would choose the extra displacement (or something else like a servo, battery, field charger, tachometer) but that is just me, I think all of the engines are beautiful
If this is a new purchase I want you to look here before buying your new engine http://www.donalds-hobby.com/prod/Scripts/default.asp put the engine in the shopping cart to see the actual price.
Old 12-15-2008, 04:38 PM
  #43  
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Default RE: Help with building a GP Big Stik 40 w/ OS .55 AX

Hey chashint !

lol.. no, I don't own all those engines... I wish ! They are the ones that I am considering for powering my GP Big Stik 60 ARF which I am presently building. I don't have an engine for it yet, as well as the Seagull Ultimate 90 that I am building.... they both need engines, and electronics and I am trying to figure out, along with the help of the members on this forum, which engine would be preferable for the Big Stik 60...
As carrellh pointed out, I will be starting a new thread to discuss the best engine options for the Ultimate. so for now, and for this thread, I am trying to determine if the 1.25 is too much and the .82 is too little for the Stik .... I am leaning towards the 100 or maybe the 115... as you point out, however, the higher displacement is certainly money better spent than on the black and gold colors of the Golden Knight in Saito's line. I hope to have the engine purchased (and decision made beforehand) before February, maybe March, depending on my schedule.

At any rate, thank you for your feedback and suggestions, they are appreciated and valued...

I did check out that website that you linked as well and see that the price for the Saito 115 is the same as the price for the 100 at Horizon, so thank you... much better pricing, and I will probably use them when I get the money and pull the trigger on one of these babies! Thanks man, I truly appreciate the tip!

Thanks so much... appreciate !

Peace.

Don

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