Sig Smith Miniplane
 

Has anyone out there put an O.S. 70 4 stroke on a Sig Smith Miniplane. If so, was there balance issues?

RE: Sig Smith Miniplane
 

I haven't built the Sig kit but have designed and built my own 1/4 scale and 1/2 scale, i doubt you will have any issues with the added nose weight.

RE: Sig Smith Miniplane
 

Mines still in the box, and was considering a Saito 82, but am concerned about having to move the firewall back to accommodate it.

RE: Sig Smith Miniplane
 

FYI.

Torque is a 2 headed ugly snake on the minplane. It will reach out to bite you and you will never get it off the ground. This bipe is SHORT coupled (Capitolized SHORT for Specific emphasis!). It will ground loop on you, and rudder management will not help you. A gyro may help as long as you only throttle into it too slow to break ground before you hit the end of a 1100ft runway. If you go with anything bigger than a .70 4 stroke, you'd be better off hand launching this bipe.

Throttle management on take-off you say?

Even with a .40 two stroke you will be breaking a sweat to get it off the ground in a straight line.

A .70 four stroke is as big as I would ever dare go.

This airplane needs to be flown on the wing. PLEASE reconsider anything at a .70 four cycle or larger unless you desire high blood pressure and bitter disappointment.

Of course, it is your equipment and I'd be curious to see somebody do this myself. [sm=wink_smile.gif]

Brian

RE: Sig Smith Miniplane
 

Thanks for the input guys! I have an old O.S. .46SF I'm considering also. Maybe this is a better choice?

RE: Sig Smith Miniplane
 

Perfect! [sm=thumbup.gif]

RE: Sig Smith Miniplane
 

I'll be starting my SMP very soon and was planning to use a Saito .56. Is this too much motor? How should the throttle be managed during takeoff to prevent ground looping?http://www.rcuniverse.com/forum/js/f...ssed_smile.gif</p>

RE: Sig Smith Miniplane
 

The Saito 56 Golden Knight is exactly what I have been using. I believe it to be a great match, but I still fought the torque (I think it is also referred to as "P" factor).

I don't think you can prevent it from ground looping all the time if you fly off of grass. When I was flying off of a paved runway in Denver, I was eventually able to get her straight down the runway fairly consistantly. Throttle and rudder management was the key. Throttle into it slowly and use your rudder.

A Gyro would help this combo significantly, but personally, I like to figure it out without the extra aid.

It will not do 3D, but will fly very well with this combo. This is the combo I used for years and I know it to work very well. It is a good match with PLENTY of muscle.

Brian

RE: Sig Smith Miniplane
 

Brian,
Thanks foryour input regarding the .56 Saito. I do fly from grass runways. I remember a .25 size Cub I had that was a nightmare to get in the air. The"P" factor you refer to, for memeans "P" down the leg until it's airborn.http://www.rcuniverse.com/forum/js/f...used_smile.gifI'm sure I'll be seeking lots of input over the course of this build. I had to locate a cheap bandsaw to cut out the printed parts. Got a good one through Craigs List. I hope the wing saddles are close enough. Probably be starting on the fuse sides today.
Thanks Again,
Dave

RE: Sig Smith Miniplane
 

I see your in Buffalo. I was told there is a free city or county fly field out there. Is this true?

As far as wing saddles, I use a mixture of microballoons and epoxy to get a tight fit. It works really well.

Brian

RE: Sig Smith Miniplane
 

Brian,
Thanks for the microballoon/epoxy tip. What / how do you get the correct angles on all the fuse side braces? In past years I would have just hand sanded them the best I could and just lived with poor fits. Unfortunately, to my knowledge there's no free RC field around here. I am a member of Wright Flyers in Monticello.
Thanks Again,
Dave

RE: Sig Smith Miniplane
 

T,

First I tape wax paper to the wing where it meets the saddle. If you don't do this, you will permanantly glue the wing to the fuse.

Then I mix my micro balloons with 30 minute epoxy. I use a lot of microballoons to the epoxy. You'll know the proper consistancy when you see it. It is similar to mixing drywall mud.

After this, I apply a good thick amount of it to the wing saddle and bolt the wing on. (Make sure you are using wax paper!) The epoxy/microballoon mix should squeeze out a bit.

I leave it set between 15-20 minutes.

Now, with a fresh straight edge razor blade, I cut the ballon mixture even withe the fuse- AFTER I pull the wing off of course. It will cut fairly easily without sticking to the knife.

Put the wing back on-WITH wax paper, and let it dry for 24hrs.

Pull the wing and paper off, shape and fill as needed, bolt the wing on and viola: PERFECT WING SADDLE!!!

Good luck.

Brian

RE: Sig Smith Miniplane
 

Thanks Brian,
what I was really asking was how to get theangles on each end of the short braces that are in the fuse sides.
Dave

RE: Sig Smith Miniplane
 

Can you take a picture for clarification? I don't think I know what you're asking.

Brian

RE: Sig Smith Miniplane
 

Brian,
My problem is that when I try to sand the joint angles by hand sometimes they don't fit so very good.http://www.rcuniverse.com/forum/js/f.../msn/48_48.gifI started the fuse assembly last nite and will probably get the second side done today. Hope the photo explains it better than my poor verbal efforts.
Dave</p>

RE: Sig Smith Miniplane
 

I watched a Smith Miniplane video on Youtube last nite in which the pilot claims to have been using an OS 70 and 12-6 prop.

Dave

RE: Sig Smith Miniplane
 

So did I. But you will also notice that not one time did he ever have control of the aircraft on take off. I remember he aborted take off at least three times because he could never control the ground looping.

The 70 will fly it, so would a G63. But I wouldn't recommend either.

I also saw a video of the mini with a Magnum .52. It had plenty of power.

At higher altitudes I would probably be recomending the .70. But even in Denver, the Saito .56 was perfect.

Regarding the fuse joints:

This is where it is a builder's kit for sure. I would lay the 1/4 square stick on top of the plan, use a straight edge and mark the angle on the stick. Then I would either cut it with my exacto knife, or better yet if you have one, use a disk sander with the table at 90 degrees to ensure a perfect angle.

I enjoy the mini build emensly. Now I'm going to have to build another! [sm=shades_smile.gif]

Brian

RE: Sig Smith Miniplane
 

Saito 62 is the best engine for this bipe....OS 70 Surpass is too heavy and big... Don't hesitate for rudder authority...If you are flying with a trainer ,you can fly with it easly...If you looked ground looping effects ,you must check the both wing incidence first and C.G. second...I made it circa 89...It was powered by OS 45 FSR ,it's very well flying characteristics ,it's smooth flier...Make it light,fly with it like delight...;)

RE: Sig Smith Miniplane
 

I`m finishing my Smith. I fact I already tried to taxi her but a few problems came up...landing gear toe-in, CG were the more anoying.
I`m rebuilding the fix points of the L/Gear, increasing Toe-in and correcting The CG point.

Mine is finished Oratex Fokker Red with yelow stripes on top of both wings. Power is a OS 46FX brand new that was laying around for the last decade or so, Bison Muffler and a Master 11X7 prop...
...and even with this 'mild' powerplant this thing goes crazy down the runway I used all my skill with the throtle/'rudder management to no no avail...here in Brasil we call this sort of behaviour 'galinha louca'....crazy chicken... :D

The problem is that my Smith wasn`t introduced to a straight line...yet!

Hope my modifications let me at least take-off...

We`ll see...

Any advice, or good ideas are always welcome

Blue skies for ALL

Tiffoso

RE: Sig Smith Miniplane
 

...and by the way, excuse my poor English...I`m realy rust and trying to do my best!!!:)

RE: Sig Smith Miniplane
 

Sorry, but I completely disagree. Neither wing incidence nor CG have anything to do with ground looping. It is directly related to engine torque and a short fuselage. The rudder can only counteract this if you throttle into it very slowly. Most RC runways are not long enough to allow enough time for this.

Brian

RE: Sig Smith Miniplane
 

Oh, the pleasures of the Mainde Flight... Yesterday (Sunday 6th Dec) at last I managed to tak off, despite the 'galinha louca' behaviour of my Smith..
In fact that`s just a problem til I could get the tail of the ground. Then it was a normal t-off.
Superb flight caracteristics, not as refined as a Ultimate but really fun to fly.
After some trimming and mild manouvers I culd do fairly good Loopings, Cuban-8, Hammerhead (Lot sof rudder!!!) and the like.

Landing was a breeze...on the final I used her caracteristic tendency to dive when in high degrees banking to align it to the runway; after that throtle down, hold a bit of up elevator to a easy point...

I`m realy suprised by the easy of operation, the bad behavior on t-off aside...

One very fun Sunday buzzing the skies...6 flights in all and I called it a day.

Hope you enjoy your`s as much as I enjoy mine.

Blue skies for all!!

RE: Sig Smith Miniplane
 

Tiffoso: No need to apologize for your use of English. You are doing waaaaaayyyyyy better than a lot of folks born and raised here in the US but saw no need to pay attention in school. And your punctuation is very good. Enjoy your Smith.

RE: Sig Smith Miniplane
 

Thanks, JollyPopper I just try to do my best... :D

I saw the posts about using a .70 4t in the Smith...I dont see how one can keep it tracking straight long enough to t-off... And I dont believe its necessary...mine is doing realy nice with a OS 46FX...of course more power wold be welcome but one has to think about all the aspects of flying not just the flight itself...

By the way I have an Os 70 Surpass with just 3 flights logged that I just instaled on the 'naso' of my beloved VQ Models Macci MC 202 Folgore wich I believe is a much more suitable combo than .704T/Smith...

just my humble opinion...

blue skies for all!!!

RE: Sig Smith Miniplane
 

As usual, if you just stab that throttle stick to full, you will have a handful on takeoff, I never got that chance to do that here in CT. Our runways are almost all grass, and unless you get there the day they mow the grass, power management is a must. I did splay the gear a few degrees and set my tailwheel as far back as possible when building it. But I never noticed any bad ground handling issues due to feeding in power smoothly and letting it build ground speed before pulling back smoothly on the stick. It's a scale plane, why would you want to yank it into the sky like a 3D machine anyway? I powered mine with a Magnum 45 abc and it flew fine, not unlimited vertical, but plenty to do anything it was asked of to do.