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Sig Smith Miniplane build

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Sig Smith Miniplane build

Old 01-31-2016, 05:25 PM
  #1251  
RICKSTUBBZ
 
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Our favorite little biplane thread has been idle to long....
I ran across this full scale "Smith" for sale the other day.
It would make a great candidate to "model"

http://www.aerotrader.com/dealers/Ai...42PF-115461210

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Old 01-31-2016, 06:13 PM
  #1252  
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LOL, was just thinking about putting my little SMP back on the flight line today. I had parked it and pulled the equipment out and put on a Contender. Lost the Contender the other day due to a failed battery. (Same battery that was in the SMP) I would rather sell the SMP though since I've moved on to larger bi-planes that I can see.
Old 01-31-2016, 06:36 PM
  #1253  
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Nice! Love the paint.

My Smithy is ready to go... just need the warm weather to come back!

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Old 04-09-2016, 09:13 PM
  #1254  
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Just found this thread, bought myself a SSM last month after eying the kit for a while. Fuselage construction begun- so far, so good! Really enjoy building kits as opposed to assembling ARF's.
Old 04-10-2016, 02:06 AM
  #1255  
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Cool- welcome to the brotherhood! If you have any questions during the build, ask. Post some pics of your progress!
Old 04-10-2016, 04:20 AM
  #1256  
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Have almost completed the basic construction and was about to mount the lower wing servo bracket before I realized how shallow the wing depth is. I was planning on using a Futaba S3004 servo which is obviously too big. What servo's have others used?
Old 04-10-2016, 05:08 AM
  #1257  
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Originally Posted by Rv7garage View Post
Cool- welcome to the brotherhood! If you have any questions during the build, ask. Post some pics of your progress!
Thanks for the warm welcome! Will get some photos when I have something worth taking pictures of LOL. Planning to build this mostly stock, though am modifying the canopy and turtldeck to look more like a Pitts Special as well as slightly changing the landing gear.

Originally Posted by Sniper68 View Post
Have almost completed the basic construction and was about to mount the lower wing servo bracket before I realized how shallow the wing depth is. I was planning on using a Futaba S3004 servo which is obviously too big. What servo's have others used?
I am planning to use either Hitec HS-81's or HS-82MG's on mine, either two sitting next to each other in the center of the wing utilizing the stock aileron linkage or laying them on their side out in the wing panels.
Old 04-11-2016, 04:44 AM
  #1258  
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Here's what I did, ace mini servo mounted on it's side. Works perfectly and no slop from additional linkage.
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Old 04-11-2016, 05:31 AM
  #1259  
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Another option is to fit a servo in a rib in each wing. You will need to beef the rib up a little. I can't recall the servos I used, they were JR mini's...around 32 oz units providing more than enough power. Had them on hand so gave them a go. I created hatches, but just covered over figuring if I ever need to get at them I can just make a couple cuts in the covering and open the door to access the servo. Never had to pull one out of a model yet in over 30 years of RC...but I am sure some day I will. Here is a link to some more pics and things that I did to mine. Love that little plane!!! Have fun!!

https://backyardflyer.shutterfly.com/builds
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Old 04-11-2016, 06:24 AM
  #1260  
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Marko- I like your solution with the servo mounted in the rib, very clean!
Old 04-11-2016, 12:37 PM
  #1261  
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Just finished framing up the fuselage, getting ready to install the firewall. Interesting that Sig suggests no down or side thrust on this one. Thinking about adding two degrees down, also wondering if raising the LE of the stab would be a better option so that centering the cowl on the prop shaft would be easier. Any thoughts?
Old 04-11-2016, 04:07 PM
  #1262  
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Originally Posted by daywalker View Post
Just finished framing up the fuselage, getting ready to install the firewall. Interesting that Sig suggests no down or side thrust on this one. Thinking about adding two degrees down, also wondering if raising the LE of the stab would be a better option so that centering the cowl on the prop shaft would be easier. Any thoughts?
See my maiden flight post #707. I intended to have 2 degrees of positive incidence in the stab, and when dust settled ended up with only 1.5 and decided to stay with that....thinking what would half a degree do. Well, I think if I had managed to get the 2 degrees in, it would have been perfect! Only slight down elevator (barely noticeable) but flies level at all throttle settings. I also have about 1 degree of down on the motor. I left mine without any side thrust and no issues with the ST .51.
Old 04-11-2016, 07:13 PM
  #1263  
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Thanks Marko, very informative post! I will go ahead and add the 2 degrees to the stab, and a degree or two to the motor. I will be using an OS 46AXII so torque shouldn't be too much of an issue there. Plan to add a couple of degrees negative to the top wing as well.

Thanks again!
Old 04-11-2016, 08:28 PM
  #1264  
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daywalker,

Hey no problem. The changes I made were due to collecting all the data I could from this thread and others, and then came to the conclusion that only a change in stab incidence was required. Folks have tried all sorts of things for this kit. Some hate the plane and others love it. It seemed that the ones that kept to the plan seemed to have a better flying model. The main complaint was having to put in down elevator to maintain level flight. Stab incidence pretty much cleared that up for me. The only reason I have about 1 degree down on the motor is cause of plan error I think, as it was not intentional. It just came out that way...although 1 degree is pretty difficult to see with the eye, but that is what came out when measured. It actually worked out well for me and I could not be more pleased with the flight characteristics of this little plane. It is just a joy to fly without any nasty tendencies. Keep in mind this is no "Ultimate Biplane" or a 3D bird, so if your expectations are leaning towards a precision flyer...that it is not. But for all out fun, and wicked snaps, tumbles and cuteness....it is right up there! I would caution you on playing with wing incidence other than what the plan calls for. It flies great without that mod. I think Rick S. was planning on testing the incidence by shimming on his old SMP, but not sure if he ever got around to it. If he is still listening, maybe he can pipe in.

That little OS should be an excellent engine for that plane. Hopefully you bolt a pitts muffler on it so it gets a more scale look!

I did not take many pictures of the servo mounts other than what I have provided. However, I completed another build of an RV-4, and did a similar configuration, with flaps as well, and took many pics if you want to see how it was done. I do like the servos attached to the hatch for a flat bottom wing, but if the wing is symmetrical then I find using a flat ply does not give the curvature needed to make it look seamless. So, then I use the rib mount method...but either should work well. Matter of preference I guess.

Here is the link to the RV-4 build with pics of the servo mounts.

https://backyardflyer.shutterfly.com/rv-4

Hope that helps.

Marko

Last edited by rc_wings; 04-11-2016 at 08:38 PM.
Old 04-12-2016, 03:34 AM
  #1265  
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Thanks again Marko, so far I have read through the first 13 pages of this thread and have picked up quite a few tips and ideas. I really like the servo in the rib idea, wish I had thought of it when I built my 4*40 with wing servos. Like you said, on a semi symmetrical wing it is tough to get a hatch to fit well.

I don't expect this model to perform like an Ultimate or even a hot Pitts, sounds like it will fly exactly how I want it to fly (hopefully LOL). I was looking for a 40 size biplane that would be a good stepping point for my larger Ziroli PT-17 and Balsa USA 1/4 Nieuport 28 and I think this one will be perfect. It even has ailerons on the bottom wing only just like the other two! The last biplane I had was a 40 size Kyosho PT-17 with a Saito 56, still my all time favorite model I have ever owned. A bit of a handful on takeoff, but it taught me to use the rudder effectively.

I did get a pitts muffler for the OS, wouldn't have it any other way!

I have bookmarked your RV-4 page, will read through that one too. I bought that kit from Great Planes last year, and the kit itself was not good at all. I used to love building GP kits, but the one I got last year had a badly scratched canopy, cracked plastic parts and broken wood. I ended up returning it, planned to get another one as I love the lines of the RV series but never did. Don't know how it got through QC.
Old 04-12-2016, 03:44 PM
  #1266  
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Too bad about the GP RV4 kit. My kit was pretty decent, except for the cowl, that required quite a bit of work to get it finished up nice. If I had to do it again, would buy a Fiberglass Specialties cowl for it. They are expensive to get shipped to Canada and my "older" buddies that winter in the south had come home already...so I was forced to bite the bullet and work with the crappy plastic cowl. Turned out pretty good in the end, time will tell how well it holds up.

Have fun with the SMP build! Lots of guys on here with experience building and flying them...so do not hesitate to ask questions. Glad to hear there will be a pitts muffler on it. Bad enough putting a 2-smoke on a bipe...let along a big ugly can muffler sticking out the side!!! LOL (says the guy that has a Super Tiger .51 on his SMP.....)
Old 04-20-2017, 10:15 AM
  #1267  
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CG Balance question? I finished my build and was shocked at how much weight I needed to add to get it to balance. I have the battery up towards the nose, running an OS 46 Fxi with a Pitts muffler and still needed to add 10.5 oz. ! I know the plane is tail heavy but this seems like a lot of weight. Anyone with similar experience?
Old 04-20-2017, 10:56 AM
  #1268  
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Default Smith Miniplane

Yep, that's not uncommon. On my SMs I mixed up lead shot in an epoxy slurry and poured it into the nose bowl surrounding the spinner hole. It was nowhere near 10 ounces, though. More like 5 to 6. Get that weight as far forward as you can.

On my 3rd SM, I went with an OS .70 4 stroke just to get "working weight" up forward. Just something to think about if you build another or wish to re-engine it later.

Don
Old 04-20-2017, 11:55 AM
  #1269  
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Leading edge of the bottom wing
Old 04-20-2017, 01:10 PM
  #1270  
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I did not have to add any weight on my Mini! I do build light, and anticipated it would come out tail heavy, so I located everything I could as far forward as possible. Needed no weigh at all and using a Super Tigger 51 with a pitts muff. Guess I was lucky!
Old 04-20-2017, 04:43 PM
  #1271  
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Marko,
How's it going?
Is your Ole Smith still logging any flight time?

Sniper,
When I originally built mine, I had no Idea what to expect, That was way before the internet and this thread...
Yep.. I had my battery mounted under the fuel tank as far forward as it would go.
Stretched the engine and cowl as far forward as I could get away with. Still had to add an ounce or two.
I'd sure look at getting anything moved that you can. 10 extra ounces will not help performance any.
And for what it's worth if it doesn't balance close to the bottom wing leading edge as 2.4Ghs mentioned, It's not going to fly as well as you might like.
A tail heavy Sig Smith Miniplane could very easily spell disaster. If it is just heavy, be sure not to get it too slow on approach.
Old 04-20-2017, 05:09 PM
  #1272  
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Hey Rick,

Going good!! Yuppers, still flying the old Smith. Have not flown it this year yet as our field is not open since things are still wet. Hopefully very soon.

How things with you? Any progress on the Pro? Mine is still in the box. Been doing too much riding of bikes and snowmobiles, and have not had the focus on building and flying lately. House renos have not helped matters either.

Marko
Old 04-26-2017, 05:54 AM
  #1273  
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Moved the servo tray forward, pushed the battery pack up to the firewall and still needed to add a lot of weight. Can't find the plans but recall the CG was about 1' - 1 1/2" from the LE. Spoke with another Club member and decided to add a larger engine, OS 61 FS. Well, it looked like a Blown Hemi in a VW Beetle. So, I'm going to try extending the engine mount approximately 1/2" using basswood strips attached to the firewall and stick with the OS 46. There's still enough room in the cowl to move it forward.

Thanks everyone for the feedback. This has got me stumped!
Old 04-26-2017, 09:34 AM
  #1274  
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I just happen to have been organizing my plans and have the SMP plans handy. The c/g on my plans is 4 7/16 inch back from the leading edge of the top wing, or just in front of the top rear mounting bolt. Where did you come up with the 1 to 1.5" measurement?
Old 04-27-2017, 09:36 AM
  #1275  
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KaP2011, I was going from memory as I couldn't locate the plans and the manual doesn't provide any info. Couldn't find any specifics on the Forum/internet. Last night I went back to the original setup with the OS 46, no weights and CG 4-7/16 back. On the first attempt, a little nose heavy. Moved the battery pack and by my third attempt nailed it. Did not need to add any weight! Fortunately, I copied the Throw Rates in my reference binder I maintain for all my planes (probably should add CG locations as well).

I really appreciate the time and effort you took to respond.

Thanks again

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