need help finishing 20 year old plane?  
View related threads: (in this forum | in all forums)

Tower Hobbies
Enter up to 4 keywords or Tower stock numbers
Logged in as Guest



Users viewing this topic: none
  Printable Version
       



All Forums >> RC Airplanes >> Kit Building >> need help finishing 20 year old plane? Page: [1]

Login
Message << Older Topic   Newer Topic >>
need help finishing 20 year old plane? - 5/16/2008 8:01:49 PM   
Popriv


 

Posts: 83
Joined: 5/5/2008
From: bellingham, MA, USA
Status: offline 		I'm jumping back in. Its been 20+ years since I flew gliders and built a few planes.
I'd like to go for powered flight now and I just happen to have a not quite finished plane thats been hanging from the ceiling for 20+ years.
I dont have the instructions or any of the unfinished parts.
Here's what I have:
53" wingspan is built and covered. alierons are missing but the control rods to them are set up, shouldnt be a problem to create these.
Fusalage is done and covered. two wheels are mounted but the nose wheel is gone.
Rudder is complete.
Elevator is not there so I will have to make one.

I'm stopping at the LHS tonight to pick up a DX6i transmitter and show them what I've got and see if they are helpful.

If I were to post a picture I'm hoping someone will know what it is?

It was a long time ago but Midwest comes to mind?. wa/is that the name of a kit companys?

I'm not sure what engine size it will take/

TIA

Steve


       Post #: 1

RE: need help finishing 20 year old plane? - 5/16/2008 10:23:01 PM   
KitBuilder



Posts: 250
Joined: 2/17/2007
From: Palm Harbor, FL, USA
Status: offline 		Post pics.... probably a 40 or 46 for motor. 20 yrs is a long time... be sure any accessible glue joints still have integrity and are not brittle or loose.
Mike

_____________________________

Mike -
Kits are made to be bashed

(in reply to Popriv)
       Post #: 2

RE: need help finishing 20 year old plane? - 5/17/2008 2:46:16 AM   
carrellh



Posts: 3320
Joined: 3/30/2003
From: Garland, TX, USA
Status: offline 		http://www.midwestproducts.com
They are a kit company and they sell other things. Their only current trainer is bigger than the one you have.

_____________________________

Regards,
Carrell

(in reply to Popriv)
       Post #: 3

RE: need help finishing 20 year old plane? - 5/19/2008 4:51:45 PM   
rlipsett


 

Posts: 448
Joined: 8/11/2003
From: hingham, MA, USA
Status: offline 		with the wingspan you have stated it sounds like a 25 size engine. we need pictures of the plane to figure it out I had the same problem as you once a 20 year old trainer with no instructions but since you have it mostle ly done it should be no problem to finish. the forward landing gear can be fairly standard so th lhs shoul have something.

(in reply to carrellh)
       Post #: 4

RE: need help finishing 20 year old plane? - 5/19/2008 6:33:22 PM   
Popriv


 

Posts: 83
Joined: 5/5/2008
From: bellingham, MA, USA
Status: offline 		I'll post a pic tonight showing where I stand.

I have a question about hooking up the control surfaces.
I havent found any info about the different methods.
1. I see wires bent to slip into the servo arm running the length of the plane and clipping onto the control horn.
2. I see the same idea but wood stock runs the length of the plane and wire is attached to each end of the wood. (stiffer than just wire?)
3. on my old gliders I liked using plastic tubes that had a plastic center shaft. threaded rods would thread into the center road and connectors would thread onto the ends. Do these have to be glued to the fuselage along their entire length or just on the ends. are these strong enough for powered flight?

Also, the nose gear and throttle control wires run through the firewall. they pass on each side of the gas tank. when I wrap the tank in foam and stuff it into position it interfering with the movement of the control wires.

This seems like a good place to use option 3 above. the outer sleeve can make contact with the foam but the center shaft should still move freely?

Like I said, I havent found a good thread yet on different option for hooking up the control surfaces.

The only things I would like the instructions for would be to show how much the control surfaces should travel? LIKE elevator up 1/2" and down 3/8"?????
and where should the CG be????


TIA

Pop


(in reply to rlipsett)
       Post #: 5

RE: need help finishing 20 year old plane? - 5/19/2008 10:02:23 PM   
carrellh



Posts: 3320
Joined: 3/30/2003
From: Garland, TX, USA
Status: offline 		Control rods:
Number 1, the wires typically run inside a plastic tube for support. Many kits and ARFs use this system. A long wire, with no support, would flex too much to be effective.
Number 2. My Sig Astro Hog, and many other models, use this method. The wooden stick gives stiffness and is fairly light.
Number 3. This is still a popular setup. One widely used system is the Sullivan Gold N Rod. Here's a link to one of the many variations: http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXFU93&P=7

With numbers 1 and 3, the outer tube sould be supported in the middle as well as at the ends. On a long rod, the more support points you have the better it will work. My planes are all number 1, metal rods inside a plastic tube.

A starting point for the CG would be 25% back from the leading edge of the wing. Measure the wing chord (leading edge to trailing edge, including ailerons) and take 25% of that number. Measure back from the leading edge. On my Great Planes trainer, that is the back edge of the wing spar but the spar location varies from kit to kit.

The Great Planes PT-20 is similar in size to your plane. These are the suggested starting control throws for it:
ELEVATOR 1/4" up 1/4" down
RUDDER 1/4" right 1/4" left
AILERONS 1/2"up 1/4" down
If no one has the numbers for your kit, this might be a good place to start.

_____________________________

Regards,
Carrell

(in reply to Popriv)
       Post #: 6

RE: need help finishing 20 year old plane? - 5/20/2008 1:02:10 AM   
Popriv


 

Posts: 83
Joined: 5/5/2008
From: bellingham, MA, USA
Status: offline
Every trip to the LHS just brings up more questions.
Thanks for everyones help.

Stopped at LHS and picked up a Spectrim DX6i TX.
These guys sell mostly helis and when I asked about servos and a batterypack to run the reciever and servos they suggested tower hobbies!
Nice guy but he didnt feel comfortable helpng me with plane stuff.

So my next area of education is what servos to buy for this .20 size, midwest Aerostar trainer, 52" wingspan, TT .36pro glow engine.

and what battery pack along with a charger to power the servos and Receiver?
Battery charging options are greater than they were 20 years ago....
I feel like I'm cheating buy asking you guys for help. What did we do before the internet?

Also, I dont think its a problem but the I think the TX is set up for Helis as thier is no clicks on the throttle as you move it. I think I read that is for helicopters????

This wouldnt effect flying plans would it?

(in reply to carrellh)
       Post #: 7

RE: need help finishing 20 year old plane? - 5/20/2008 4:26:52 PM   
carrellh



Posts: 3320
Joined: 3/30/2003
From: Garland, TX, USA
Status: offline 		Before the internet, people got info from other people by going to the field and talking face to face. Also, some decent info was in the modeling magazines. Or, they just experimented until they found something that worked.

The plane you have should use "standard" servos. As long as they have about 40 ounces of torque at 4.8 volts they should be fine. Choosing a servo with one or two ball bearings on the output shaft will give smooth performance and reduce wear on the case and shaft.
Some choices of relatively inexpensive standard ball bearing servos, listed alphabetically:
Airtronics 94322Z
Futaba S3001 or S3004
Hitec HS-325HB or HS-425BB
Hobbico CS-67
JR 537
JR Sport ST47BB
Tower Hobbies TS-67
I'm sure there are more choices that would work well. These are the ones I could find in a few minutes. Everyone has a favorite but any of these will serve you well.

The charger that came with the DX6i should also have a lead to charge 4.8 volt receiver packs. The pack that comes with the DX7 is a 4.8 volt 1100 mah nicad pack, so I'd consider 1100 mah to be the minimum capacity to consider. I have a bunch of 1650 mah nimh packs that I bought from www.hangtimes.com which is also known as NoBS Batteries.

_____________________________

Regards,
Carrell

(in reply to Popriv)
       Post #: 8

RE: need help finishing 20 year old plane? - 5/20/2008 5:10:16 PM   
carrellh



Posts: 3320
Joined: 3/30/2003
From: Garland, TX, USA
Status: offline 		I downloaded the manual and it doesn't mention smoth vs racheted throttle. It says the DX6i has airplane and heli programming so it works for both, you choose plane or heli when you set up a model in the programming. Some people prefer the smooth throttle of a heli transmitter, others like the 'clicks' of a racheted throttle. I've never used a smooth throttle so I have no idea if I'd like it.

_____________________________

Regards,
Carrell

(in reply to Popriv)
       Post #: 9

RE: need help finishing 20 year old plane? - 5/20/2008 6:32:41 PM   
Popriv


 

Posts: 83
Joined: 5/5/2008
From: bellingham, MA, USA
Status: offline 		Found another LHS I'm going to visit tonight.
looking for the following:

I need 4 standard servos, can I mix new servos with 2 old futabas that are in a glider that was flown about 20 times?
I dont think I need digital servos for this trainer?

Battery pack and charger. Spectrum DX6i calls for 4.8 volts. Can I get a 6 volt to be safe?
I've been studying up on the battery charger option... WOW??? I may settle for the cheapest thing that will charge whaever battery pack I buy BUT Based on future plans for electric flight I would like to buy one charger that would do everything? $50 - $75 I'm guessing.

An assortment of control surface connectors so I can figure out the best way to hook up.


Buying the $300 kit would have been easier!
I'll spend the same/more getting my 20 year old plane flying.
But I'll have the radio I want and its the principle of finishing this plane and seeing it fly after 20+ years hanging from the ceiling...


steve

(in reply to carrellh)
       Post #: 10

RE: need help finishing 20 year old plane? - 5/20/2008 9:04:56 PM   
carrellh



Posts: 3320
Joined: 3/30/2003
From: Garland, TX, USA
Status: offline 		You can mix brands and you can mix digital and analog in the same model. I agree that digitals are not needed in your trainer and possibly not in many future planes. As long as the Futabas still work I would use them and save a few bucks right now.

As long as you have a high capacity battery pack you do not need 6 volts in this model. The extra cell is more weight to haul around. You can buy a simple "wall wart" charger from www.hangtimes.com that willcharge high capacity packs (4.8 or 6.0 volt) overnight and it costs maybe $20.

You can get AC/DC peak detection chargers, and cyclers, for more money but you do not have to have one to get started.


You are right that you're spending more than it would have cost to just get a RTF package, and the RTF would be easier to get flying. The small hardware adds up. But, you have bought a transmitter that has features to support many different planes and helis and it can store settings for 10 models. That's the majority of what you're spending and it should last you a long time.

The biggest plus to what you're doing is the feeling you'll get the first time your kit built plane lifts off the ground.

_____________________________

Regards,
Carrell

(in reply to Popriv)
       Post #: 11

RE: need help finishing 20 year old plane? - 5/20/2008 9:31:49 PM   
carrellh



Posts: 3320
Joined: 3/30/2003
From: Garland, TX, USA
Status: offline 		For your control linkages:
Something similar to these will be needed to thread onto the ailron torque rods. Several sizes are available so you'll have to measure the rods that are in your wing.
http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXDMK2&P=0
The actual aileron pushrods going from the servo to these connectors can be something like this
http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXD884&P=0

If you want to install the pushrod tubes, something like this (or Sullivan Gold N rods) should work for the elevator and rudder. I also use these for throttle and nose gear steering. Sometimes there's a good bit of wasted wire and outer tube. I save all of it because it seems to eventually get used.
http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXK059&P=SM

Where the pushrod goes through the servo horn I make a 90 degree bend in the wire and use these locks
http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXAZC3&P=0

For elevator and rudder control horns, something like these seem to be the most common
http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXD933&P=0
http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXK108&P=0

_____________________________

Regards,
Carrell

(in reply to Popriv)
       Post #: 12

RE: need help finishing 20 year old plane? - 5/21/2008 1:11:15 AM   
Popriv


 

Posts: 83
Joined: 5/5/2008
From: bellingham, MA, USA
Status: offline 		Thanks for the links.
I found another LHS and this guy is a "plane" guy so he was helpful. Didnt seem to just push stuff at me.
Seemed to put some thought into what was best for my situation.

We are slow at work so I have spent hours researching.

I picked up:
Hydramax Ultra NiMH Battery. 4.8 1200mAh
After much discussion I went with a Hobbico quick field charger Mkll.
I have to create my own adapter to charge the battery. does that sound normal? (I can easily do this)
At some point I think I would want something to balance and check the condition of the batteries? how important is this?

My options for the glow igniter?
I see the rechargeble ones for $16 - $25 or a connector to a 12 volt battery?

Chicken stick good enough to start?


Gotta go Celtics are on!!!

Pop

(in reply to carrellh)
       Post #: 13

RE: need help finishing 20 year old plane? - 5/21/2008 1:52:01 AM   
Popriv


 

Posts: 83
Joined: 5/5/2008
From: bellingham, MA, USA
Status: offline 		OK, battery has 3 wires comming out of it, only the black and red are connected to the charger?
what is the 3rd wire, (white) for?

I have a 6" extension that I'm soldering bananna plugs onto. I'll have to do this for whatever batteries I charge with this..

pop

(in reply to Popriv)
       Post #: 14