RE: CD ScaleDesigns Sopwith Snipe build  
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RE: CD ScaleDesigns Sopwith Snipe build - 3/8/2008 11:11:35 AM   
geezeraviation


 

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From: Houston, TX, USA
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[of quote]ORIGINAL: geezeraviation
I'd put it at about 30-35 degrees. For some reason when I have the servo/radio setup for maximum motion, I get at least 5 degrees more movement to the left than to the right. I can't explain this.
[/quote]
That's certainly plenty of rudder, I fly biplanes from a 38" Dreamer to a 93" Willow on floats with a 1/6 Moth a 1/8 Tabloid on floats and two quarter scale models in the mix, no blanking or rudder ineffectiveness noted. The differential in rudder travel is best explained by a term used by one of my Air Force tech school instructors explaining how a certain section in the front end of a threat receiver worked-FM-and it's not related to freq. modulation. Happy landings, Doc. Try a new plug in that Saito.

< Message edited by geezeraviation -- 3/8/2008 11:13:26 AM >

(in reply to abufletcher)
       Post #: 1351

RE: CD ScaleDesigns Sopwith Snipe build - 3/8/2008 11:51:33 AM   
Sethhunter


 

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Joined: 6/20/2005
From: Princeton Junction, NJ, USA
Status: offline 		Hi Don - ship looks fantastic. It's been great to follow along with your build and can't wait to read (see?) the maiden. Just a thought on the spraying (not that I'm an expert by any means) - I was able to get the dusting affect provided the paint was thinned enough, and the gun (standard hp gun) was clean. I found tiny bits of build-up of dry paint inside the tip would lead me to change the pressure, causing the paint to spray too heavily (or not at all). Thinning and cleaning - worked for me.

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(in reply to abufletcher)
       Post #: 1352

RE: CD ScaleDesigns Sopwith Snipe build - 3/8/2008 12:22:09 PM   
abufletcher



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quote:

ORIGINAL: Sethhunter
Hi Don - ship looks fantastic. It's been great to follow along with your build and can't wait to read (see?) the maiden. Just a thought on the spraying (not that I'm an expert by any means) - I was able to get the dusting affect provided the paint was thinned enough, and the gun (standard hp gun) was clean.


Well, I think the main problem is that it's not really "paint" that I'm spraying. It's PU and Nelson's clear. The PU is already very watery. The Nelson's is very thick (viscous) but cut 1:1 with water is about the same as the PU. If I were going to be spraying a flat surface I could lay on a level surface it would be ok, but there's no way I could spray the fuselage with either of these (as I need to do to seal the markings). I also need to fuel-proof the grey areas which will be sprayed (from a can) with normal acrylic model paint.

Hey, Geezer ( ) I think I'll take your advice and change the plug. But, you know, unless I can get that smooth idle I got with the glow starter on, I'm might decide to go with an onboard glow system. The sound and smoothness was almost too beautiful for words!

(in reply to Sethhunter)
       Post #: 1353

RE: CD ScaleDesigns Sopwith Snipe build - 3/8/2008 3:17:29 PM   
vonJaerschky



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Joined: 8/25/2002
From: Comox, BC, CANADA
Status: offline 		Ah, another reason I don't miss glow. When the need for nostalgia strikes, I dig out my Astro Hog with O.S. FS-90 (the original version with the pushrods in the back) and head out to make some smoke and noise. I'm curious what plug you might be using in the Saito. I had a few Saitos, and they all ran really well with the Fox Miracle Plug and 10% nitro fuel, as does the OS. Maybe check for any air leaks around the intake pipe/head joint and the carb/intake pipe joint, too. I hope you get the problems sorted out.

< Message edited by vonJaerschky -- 3/8/2008 3:21:32 PM >

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       Post #: 1354

RE: CD ScaleDesigns Sopwith Snipe build - 3/8/2008 3:25:54 PM   
FokkerAce


 

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From: Cortland, NY, USA
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quote:

ORIGINAL: abufletcher

quote:

ORIGINAL: geezeraviation
Don if your 1 1/2" gives you 35 or 40 degrees of travel thats probably all you'll need but if it only gives you 20 degrees then you need to fix it.


I'd put it at about 30-35 degrees. For some reason when I have the servo/radio setup for maximum motion, I get at least 5 degrees more movement to the left than to the right. I can't explain this.


You've probably alreaady figured this out, but if you're 5 degrees different [at the servo or the rudder?], then the servo arm isn't centered on mechanical center.....may not be fixable....depends on the spline spacing of your servo.

FA

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       Post #: 1355

RE: CD ScaleDesigns Sopwith Snipe build - 3/8/2008 3:35:20 PM   
abufletcher



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quote:

ORIGINAL: FokkerAce
You've probably alreaady figured this out, but if you're 5 degrees different [at the servo or the rudder?], then the servo arm isn't centered on mechanical center.....may not be fixable....depends on the spline spacing of your servo.


This is after I've done the servo centering with the radio. I suppose there is some possibility that one of the control runs ended up being just a bit longer or shorter than the other. Anyway, either I'll figure it out, or learn not to care!

(in reply to FokkerAce)
       Post #: 1356

RE: CD ScaleDesigns Sopwith Snipe build - 3/8/2008 3:45:58 PM   
abufletcher



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quote:

ORIGINAL: vonJaerschky
I'm curious what plug you might be using in the Saito. I had a few Saitos, and they all ran really well with the Fox Miracle Plug and 10% nitro fuel, as does the OS. Maybe check for any air leaks around the intake pipe/head joint and the carb/intake pipe joint, too. I hope you get the problems sorted out.


I'm not really sure what brand plug it is and I suppose that's part of my problem. It may be whatever plug came with the engine. Actually, the engine once I get the settings right should be great. It starts up quick and strong. I haven't played around much with manual starts but it jumps to life almost as soon as I get the electric starter on it. I've got four other Saitos, so yeah I've had a generally good experience with them. That having been said, the best, most reliable engine I own is a 52 Magnum (actually I've had two other 52 Magnums and one of the others was a total dud).

Anyway, I suspect I'll get it sorted out. Besides this is exactly why I mounted it in the "practice plane" instead of the Snipe. By the time I put it in the Snipe, I want to know its operation inside and out.

BTW, I wanted to add that I really appreciate all the advice throughout my build. I'm a big believer in the idea that if you ask enough stupid questions you eventually get pretty smart.

< Message edited by abufletcher -- 3/8/2008 4:16:06 PM >

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       Post #: 1357

RE: CD ScaleDesigns Sopwith Snipe build - 3/8/2008 7:21:50 PM   
geezeraviation


 

Posts: 109
Joined: 11/4/2007
From: Houston, TX, USA
Status: offline 		I like an onboard glow for more than one reason, the reliability and smoothness of the idle and not having to fiddle with a nistarter to start the engine and depending on how the engine is mounted a hole in the cowl some times is undesireable. I use an O.S type F plug in a Saito 180 I have but a flying pal uses that Fox Miracle plug, we both use 20-20 fuel. Later , Doc

(in reply to abufletcher)
       Post #: 1358

RE: CD ScaleDesigns Sopwith Snipe build - 3/9/2008 1:41:38 AM   
JohnF


 

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From: toms river, NJ, USA
Status: offline 		Don, The only stupid question is the one you don't ask.

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RE: CD ScaleDesigns Sopwith Snipe build - 3/9/2008 9:49:30 AM   
abufletcher



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From: Zentsuji, JAPAN
Status: offline 		Yes, today was a better day! The Saito 72 was running perfectly thanks to a change of glow plug and the tuning help of the our resident Saito engine expert (who has personally visited the home of the late Saito president). He got the engine ticking over smoothly at 10400 on the top end and 2500 at idle. Silky smooth and oh what a beautiful sound! And this led immediately to the successful maiden of the Cub. The take-off was a bit more of an adventure than I would have liked due to high rates on the elevator. But once I switched to low rates it flew steady as a rock (maybe that's not a good metaphor for an airplane) without needing any trim whatsoever. Aileron control was a bit sluggish on low-rates but it turned nicely and flew very scale at 1/2 throttle. I didn't do anything fancy, just a few circuits around the field and the landing was uneventful. However, I did notice that two CA-joints on the wing bracing struts had come loose so I suppose it's good that I didn't push it.

The weather was perfect again with just the lightest of breezes, cool and sunny. There were a lot of guys out for the day but the two most interesting "birds" were a couple of identical scratch-build electric versions of the historical Japanese model that pre-dates the Wright Bros. Only a model was ever constructed because at the time (mid 1880's) no suitable engine was available. The little scale version has its wings build on a special curved building board and flies with elevons. There were also a couple of Kite-shaped gliders (as in the bird) that ended up attracting the attention of the real thing:

http://web.mac.com/dcarroll2/iWeb/Site/Sanuki%20Wings%20and%20Kites.html

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< Message edited by abufletcher -- 3/9/2008 11:44:21 AM >

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       Post #: 1360

RE: CD ScaleDesigns Sopwith Snipe build - 3/9/2008 5:17:39 PM   
abufletcher



Posts: 5157
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From: Zentsuji, JAPAN
Status: offline 		I do have some small paltry progress on the build to report. I've removed all the panels in preparation for painting and also to work on the mechanicals. What it was all disassembled did the following:

*fuel proofed the firewall
*installed the switch so that it can be turned on and off through the round hole in the side panel
*made a slot to reroute the aileron servo cable so it doesn't have to travel through the cockpit area
*routed the antenna around the cockpit (around the side formers)
*made the bottom belly hatch with aluminum up front (badly) simulating the V-shaped pan on the original
*got the M2 hex bolt and driver to adjust the needle valve

I had hoped to have the turtledeck and panels painted by now but there are too many experiments still pending.

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       Post #: 1361

RE: CD ScaleDesigns Sopwith Snipe build - 3/9/2008 7:30:00 PM   
FokkerAce


 

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From: Cortland, NY, USA
Status: offline 		Paltry doesn't belong with anything that you've shown us......beautiful plane!

FA

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       Post #: 1362

RE: CD ScaleDesigns Sopwith Snipe build - 3/10/2008 1:40:31 AM   
allanflowers



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From: San Diego, CA, USA
Status: offline 		On the differential issue (based on your drawing in post 1332), I think there is a problem. The differential imbalance is made worse by the slight angle in the tail but most of the problem comes from the extreme angle you have at the front of the rudder linkages. If you apply the fix suggested in the next post # 1333 (by FokkerAce?) you will be better off.
I copied your basic layout on my Pup but thought it was worth angling my servo horns for this reason. (see pix)
You might look at crossing the lines at the back which MIGHT compensate for the differential created at the front - as an alternate approach.


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