H9 P-40 Warhawk and CJM Retract Issues  
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All Forums >> RC Airplanes >> RC Warbirds and Warplanes >> H9 P-40 Warhawk and CJM Retract Issues
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H9 P-40 Warhawk and CJM Retract Issues - 10/29/2006 5:46:31 PM   
Ace9


 

Posts: 138
Joined: 9/21/2003
From: Brandon, MB, CANADA
Status: offline 		Hello everyone; I have just received my Century Jet Models Inc. retracts (part# 34088) There is some problems with them regarding fitting. #1) The 4 holes drilled in the main mounting plates are off by the diameter of one hole. 2) The main mounting plate is physically larger than the OEM H9 gear so they don't fit into the wing cavity. 3) The length of the main gear struts are 20mm to short which will cause the wheel to not go inside the wheel well hole cut in the wing when the gear is retracted up inside the wing because it is not centered. Has anyone ran into these issues before? And if so, which one(s) of the above 3 mentioned.

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RE: H9 P-40 Warhawk and CJM Retract Issues - 10/29/2006 10:01:25 PM   
lthibault



Posts: 358
Joined: 1/9/2005
From: Gatineau, QC, CANADA
Status: offline 		Hi Brent,

please refer to the pictures.

1) Was your landing gear legs the same length as the OEM H9 gear to allow the wheel to center [iin the wheel well?


The length of the LG is 18 cm or 180 mm as you can see on the picture. I don't know the length of the original H9 gear. As you can see, the wheel is on the spot.


2) Where the 4 holes in the main landing gear plate drilled in the right spot to perfectly match up to the holes drilled in the wood mounts in the wing?

I don't think so. I had to do a lot of grinding, sanding and wood reinforcement to accomodate the new retract.



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< Message edited by lthibault -- 10/29/2006 10:20:07 PM >

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Luc

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RE: H9 P-40 Warhawk and CJM Retract Issues - 10/29/2006 11:04:55 PM   
Ace9


 

Posts: 138
Joined: 9/21/2003
From: Brandon, MB, CANADA
Status: offline 		Thanks a million for the photos Luc. I will get a couple of shots within the next 8 hours. I think it is a mistake in which all of the plates are being drilled at incorrect distances. You see, the OEM H9 plate holes are at 27mm center to center going parallel with the wing while they are 31mm center to center going parallel with the fuselage. The CJM's plate holes are at 31mm center to center going parallel with the wing while they are 27mm center to center going parallel with the fuselage. The 2 different distances are correct, however they have been transferred to the mounting plate the wrong way.

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RE: H9 P-40 Warhawk and CJM Retract Issues - 10/29/2006 11:05:16 PM   
LDM


 

Posts: 5476
Joined: 5/29/2003
From: Denver, PA,
Status: online 		Are you trying to make the gear fit in the exact same location as drop in wihout adding new rails or reinforcements ?

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LDM

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RE: H9 P-40 Warhawk and CJM Retract Issues - 10/29/2006 11:52:24 PM   
Richard L.



Posts: 8775
Joined: 7/28/2002
From: Redmond, WA, USA
Status: offline 		CJM retracts, like most aftermarket air retracts, are not meant to be a direct drop in. One must widen the stock mounting rails, epoxy in additional wooden blocks, and drill new mounting holes. This also applies to Robarts, Sierra, etc...

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RE: H9 P-40 Warhawk and CJM Retract Issues - 10/30/2006 12:48:22 AM   
LDM


 

Posts: 5476
Joined: 5/29/2003
From: Denver, PA,
Status: online 		yep that is where my question was going

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LDM

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RE: H9 P-40 Warhawk and CJM Retract Issues - 10/30/2006 4:20:54 AM   
lthibault



Posts: 358
Joined: 1/9/2005
From: Gatineau, QC, CANADA
Status: offline 		I totally agree with the previous comments. This is not a "plug and play'' situation.

Be ready to use that Dremel and make a lot of dust ..then you will need to put new blocks, epoxy, sand... until you get the right angle.

Maybe that I should not mention how many hours I had to spend sanding those blocks before the fit was right...

Then I had that pesky air tank leaking...

But hey, it's all over now...they look great and work fine.

Now there ain't noting I can do about another major problem: WINTER

< Message edited by lthibault -- 10/30/2006 4:26:01 AM >

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Luc

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RE: H9 P-40 Warhawk and CJM Retract Issues - 10/30/2006 4:48:57 AM   
Ace9


 

Posts: 138
Joined: 9/21/2003
From: Brandon, MB, CANADA
Status: offline 		Here is some photo's of what I'm talking about. I just understood that when a company says, Cut to Manufacturer's Specifications and Specifically designed for Hanger 9 Aircraft, then there would not be a need for having to re-drill any holes. Since some other gear sets include a wing modification drawing I just figured that they would for the better part simply drop in. I just find it an interesting coincidence that the hole center to center just happens to be correct if you give the plate a 1/4 turn! If I have to re-drill holes and/or narrow the main plate to fit inside the wing cavity, I will do it. However I don't know what to do about the length of the struts as they are 20mm (25/32" to short and they won't allow the wheel to go inside the circle cut in the wing since this causes the wheel to rub on one side. This was one of the major selling points for me was the ease of installation due to the gear was specifically designed for the Hanger 9 P-40 Warhawk . I love the look and really appreciate the quality of well made products as these are truly a work of art and that is another reason why I chose this gear over some of the others. What would be really interesting to know is some actual measurements from someone else's gear just like I measured mine. Both measurements were taken with the gear at 90 degrees in the gear down position, so as to keep a uniform measure for comparison purposes. I would also like to thank LDM and Richard L for opening some good suggestions which I hadn't even thought about let alone considered.

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RE: H9 P-40 Warhawk and CJM Retract Issues - 10/30/2006 5:33:23 AM   
Ace9


 

Posts: 138
Joined: 9/21/2003
From: Brandon, MB, CANADA
Status: offline 		Well upon another look at lthibault's photo of the ruler showing 180mm, I went out and measured mine. Guess what, it measured the same. I then figured that if lthibault's gear retracted into the OEM hole in the wing why won't mine. I then eyeballed up the holes and held my new gear in the same for/aft position as the OEM gear would be positioned in reference to the wing and then manually retracted the gear. Guess what, the spindle was totally centered in the middle of the circle. How can that be as the gear is clearly 20mm shorter in the gear down and yet seems to grow that 20mm when the gear retracts into the wing. The secret is in the pivoting of the strut and how it goes inside the main frame as it goes to the gear down position. When it goes to the gear up position the way the mechanical geometry is set up, the strut actually comes out of the main frame causing it to effectively gain length in relation to it's mounting position. This is great news as this was my biggest concern. The aircraft will sit 20mm lower than the OEM gear, however since the gear gets longer when retracted back into the wing it won't be a major issue. I took a couple more photo's to help explain. I do still think that someone accidentally drilled the holes backwards though!

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< Message edited by Ace9 -- 10/30/2006 11:44:28 PM >

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RE: H9 P-40 Warhawk and CJM Retract Issues - 10/30/2006 10:50:07 AM   
LDM


 

Posts: 5476
Joined: 5/29/2003
From: Denver, PA,
Status: online 		Usually when they say "made for a plane " they really mean that the general length of the strut leg will be the correct size for the plane or the angle of retract /extension is correct for the plane. In addition the mounting rails will also be expected to fit but not as drop ins .
Most of the h9 after market retracts need you (or you should ) reinfoce the inner wing sheeting area , remove , or reinfoce or add totally new rails from the base up .
In addition why plant a $250 tree in a $5 hole , so most of us will make new wheel wells that will fit larger wheels (if you choose) .The wells can be made of balsa , fiberglass ect and you just fill in the wing gaps with sheeting .
I know its all more work but if you take your time and do it correctly now you will be very happy with the results .

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RE: H9 P-40 Warhawk and CJM Retract Issues - 11/2/2006 1:18:33 AM   
Ace9


 

Posts: 138
Joined: 9/21/2003
From: Brandon, MB, CANADA
Status: offline 		Thanks LDM for the info. I decided to weigh both systems comparing OEM to CJM retracts. Here are the results. H9 complete system is 215 grams (7.58 oz) which include both mains, both bell cranks and both pieces of wire coming off of the bellcranks. CJM complete system is 453 grams (15.97 oz) which includes both mains, pressure tank, control valve, fill valve, 4 line couplers., 4 T's, 64" black line and 64" red line. I have a photo that displays everything I weighed that will go into the airplane minus a few inches of line which will be determined once it has been cut to the length required. The difference comes out to be 238 grams (8.4 oz). Once all of the modification's have been done in order to install this system it will definitely be a good system no doubt!! Ace9.

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Remember cleaning your aircraft at the end of the day is good because you still have it!!

(in reply to LDM)
       Post #: 11

RE: H9 P-40 Warhawk and CJM Retract Issues - 11/2/2006 2:31:55 AM   
LDM


 

Posts: 5476
Joined: 5/29/2003
From: Denver, PA,
Status: online 		Ace , remember the H9 system takes a retract servo , the CJ can use a micro servo for actavation , that is some weight savings , not much but some .
Good luck I think you will be very happy with the CJ gear

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LDM

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       Post #: 12

RE: H9 P-40 Warhawk and CJM Retract Issues - 11/6/2006 5:43:39 AM   
Ace9


 

Posts: 138
Joined: 9/21/2003
From: Brandon, MB, CANADA
Status: offline 		Thanks for the tip LDM; I weighed a GWS Pico Std+ servo which came in at 6 gms which will be replacing my Futaba FP-S136G retract servo which weighed in at 44 gms. That will give me a difference of 38 gms (1.34 oz) lighter bringing the actual weight gain down to 200.15 gms (7.06 oz). I have a couple of electrics and I know that any weight saving is worth it. Again, thanks as I wouldn't of thought of it! Ace9.

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Remember cleaning your aircraft at the end of the day is good because you still have it!!

(in reply to LDM)
       Post #: 13