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Typhoon Retracts

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Hawker Typhoon

Hawker Typhoon

The plan build article from 2007 by Tony Nijhuis - 23/4/09

Richard Acland12/10/2007 18:04:00
130 forum posts
70 photos

I propose to build the Typhoon from the free plan.I have ordered the cowl and canopy and (correct) size plan. I need to know which make of retracts were fitted to the original so that I can have them ready to start building. Any help appreciated.

                                                                         R. A.

David Ashby - Moderator13/10/2007 06:55:00
11058 forum posts
1740 photos
619 articles


 Tony used a set of mechanicals from Unitracts International 01474 359990.


Grimreaper14/06/2008 10:25:00
20 forum posts

how much were they ??

Walts14/06/2008 12:12:00
193 forum posts
86 photos

Look down the page on this link for the Tony Nijhuis designs, you will see the sport delux units at £24 a pair (units only) These are what the model was designed for, but Unitracts have another all metal option if the model is likely to be heavy.


Grimreaper14/06/2008 12:43:00
20 forum posts

cheers thanks for that, i've just found the ones im after on towerhobbies, there pneumatic. 90deg operation should be enough throw ??????

PhilO10/06/2011 18:53:36
23 forum posts
I am just getting ready to cover my Nijhuis Typhoon (I'm a slow builder)
Engine is in and Retracts fitted. PROBLEM - I found that the recommended SuperTecLo-Profile 136GH/2BB servo was not man enough to retract the pair of robart legs and wheels and have had to fit a second servo, one for each leg.
I now want to fit a separate retract battery and switch as articled in a recent RCM& E which i have unfortunately lost or mislaid.
Can anyone please help me here, I seem to remember that a wire had to be cut somewhere. Was it the white,red or black to the receiver retract channel?
Thanks in anticipation
Alan Cantwell10/06/2011 19:24:05
3039 forum posts
its the red wire from the reciever,                     look below, 
       i did say the white wire,   oops,   wouldnt be any   good on bomb disposal would i?

Edited By Alan C on 10/06/2011 19:30:37

Alan Cantwell10/06/2011 19:26:04
3039 forum posts
what goes up
PhilO12/06/2011 14:03:33
23 forum posts
Have followed the wiring diagram and turned on but nothing doing.
I tested the servos by direct connection into channel 5 and still no joy so it looks as though I may have fried both servos although did not smell anything.
I reversed the polarity (red to black and visa versa) on one of the servos to try and get them to run in opposite directions. Could this be the problem although can't see why it should have blown both.
Do you know of a good servo repairer? After the problems ive had in trying to get these retracts to work, I think I will stick to fixed undercarriage models in future.
EWWBUP ( which not surprisingly stands for every which way but up)
Alan Cantwell12/06/2011 20:51:48
3039 forum posts
you did only cut the red wire from the reciever didnt you? the idea is to still get the signal function, and the negative, but the power bit comes from the 2nd battery,
Handyman12/06/2011 21:53:06
218 forum posts
1 photos
Hi Phil, sounds as though you have a problem there.
I would first of all test the servos separately before you cry "Fire". You say that you tried to reverse one of the servos by reversing the black to red and vise a versa. Well did you also reverse the 3 connections on the feedback potentiometer as well. Then the servo will reverse. I am sure that our learned friends on this site will bear me out on this
PhilO12/06/2011 22:06:10
23 forum posts
Thanks guys.
Yes I did only cut the red wire Alan, so I guess that the problem arose from reversing the polarity on one of the servos as I have tested them again on a single lead direct from the receiver. As I gave it no more than 4.8 volts I wouldn't have thought this would have caused a problem though!
Handyman, is it a simple task to reverse the potentiometer connections. I assume I have to take the cover off? (sorry for being a pleb in the electronics field)
ps: have found a pair of screwjack units on ebay which look as though they may be a simpler solution. If I can get at least on of the servos to work again will probably use to lift the u/c doors

Handyman12/06/2011 22:09:30
218 forum posts
1 photos
Alan C. Are we missing something here. I read that that Phil is using two servos, one for each retract. If that is the case, should he not use two "Y" leads to get the power to both servos.
Not wishing to hi-jack Phil's posting but I am about to change my mechanical retracts for a pair of electrical ones and I would also like to use a seperate battery. Would your circuit work for these also.
Handyman12/06/2011 22:12:55
218 forum posts
1 photos
Phil, it can be a bit of a fiddly job and you need a small soldering iron, but if you take your time it should not be a problem. And yes, you do have to take the servo apart!!!!!
PhilO12/06/2011 22:28:25
23 forum posts
Thanks handyman. I have 2 y-leads in the circuit as you suggest but the problem seems to be with the servo as I have tested them both on a direct lead to the receiver. Putting another servo in port 5 works normally
Handyman12/06/2011 22:53:01
218 forum posts
1 photos
Hi again PhilO. This may be a daft question but did you test these retract servos separately before you began to experiment with seperate batteries. To have two fail at the same time seems very unusual???? Tony.
Tim Mackey12/06/2011 23:04:10
20920 forum posts
304 photos
15 articles
Am I missing something here. If PhilO simply reversed the connections to the servo, the circuitry as well as the motor will have suffered revers polarity !
To get the direction changed, one needs to swap the wires on the motor, and the pot, NOT the whole servo.
Easier to buy a servo reverser.

Edited By Tim Mackey - Administrator on 12/06/2011 23:04:58

Alan Cantwell12/06/2011 23:20:41
3039 forum posts
what you should have is a Y lead plugged into the RX, with a Y lead plugged into one of the outputs, this is for the 2 servos, the remaining lead of the Y into the RX carries the switch, so you should be using 2x Y Leads,
Did you test the servos before you set them up? only the red wire into the RX on the retract socket has the red wire cut, The power goes to the servos through the junction of the 1st Y lead, it cannot go into the RX, cos the reds cut, 4.8 is enough, if reversed, to fry each and everyone of the servos, but generally, purple smoke is given out, and an acrid smell of burning, if you have not had the last 2, then the servos are not getting power, what make are they?
PhilO13/06/2011 10:29:04
23 forum posts
Servos are Supertec S136 GH.
Both servos were working and lifting the gear on test. Problem started when I fitted the by-pass loom and reversed polarity - no servo response whatsoever.
Have opened up one of the servos and visually all seems in order - no burning smell and no burnt components. When I connected a standard servo to port 5 this worked fine but when I did similar with the retract servos, again nothing therefore cannot be lack of power and must be some electronic component failure.
PhilO13/06/2011 11:42:12
23 forum posts
Have spoken to Mike at Model Radio Workshop @ explained the situation.
He says reversing the polarity manually rather than electrically has blown the amplifiers. a stupid and relatively expensive mistake.
Doesn't think it is economic to repair but I hate to be beat so if anyone has a pair of broken SUPERTEC S136 GH servos ( with electronics board intact) I will make them an offer .

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