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.

RE: Sig Smith Miniplane
 

Has anyone tried putting in some right engine thrust to try to help offset the ground looping tendencies? The drawings show no thrust line offset but this would seem to be a proper corrective action or am I just missingthe pointsomehow?http://www.rcuniverse.com/forum/js/f.../msn/50_50.gif</p>

RE: Sig Smith Miniplane
 

Yes. It doesn't help the gound looping at all, but is worth while for trimming it out.

Just throttle into your take off slowly to keep her under control.

RE: Sig Smith Miniplane
 

Thanks Bipes,
I have also seen a few posts which seem to suggest a need for some down el. to retard a tendency to climb. I wonder if this is a result of incorrect wing incidence or simplya need for some down engine thrust.

RE: Sig Smith Miniplane
 

Probably both. I'd wait to change much until you get it in the air to see what your's does. No two airplanes will fly the same.

There is A LOT of lift in that small wingspan. Add that to a very light wing loading (...even when it could end up over 7lbs-which is very unlikely. It'll probably finish between the 5-6lb range), and there isn't much you can do but manage throttle to keep it from climbing.

The fact that it has a "virtual" (:D) flat bottom wing doesn't help matters either.

Brian

RE: Sig Smith Miniplane
 

Don`t know if you guys read my last report on the other thread, so ...

"Finally I tamed of my Smith...

The 'galinha louca' (crazy chicken) behaviour on the ground I solved by installing the Cessna 180 type landing gear with the wheels with heavy toe-in plus training the rudder control and the tyming to acelarate. T-Offs now area breeze, even with crosswinds...she wants to face the wind but with litle (VERY LITLE) rudder input she tracks straight up.

In the firts weekend (6 flights, post above...), with some 450gr of lead glued to the firewall to keep the CG as per plans I had a slightly touchy Smith and couldn`t trimm to perfection...fun but far from perfect.

I ripped of the lead, instaled a new engine mount, placing the engine 4,5cm (that`s nearly two inches, I believe...) ahead of the original position and placed the on board battery fixed to the Firewall, beside the engine . The Battery was isolated from vibration and fuel, of course. This way I have perfect CG and a much lighter Bipe.

With less 450gr my Smith became another plane. T-offs are 1/4 shorter, she climbs like a rocket (I told you guys the old .46FX was a good choice...), does anything but 3D...

I couldn`t be happier with this plane...

Now I just need some touch`n go training to get perfect 3 point landing...wich I almost did a couple of times...almost!!!

Just one word of caution...when landing tail up with tha high degree of toe-in she likes to nose down...solution...3-Point landing...besides...3-points are much more impressive...

Blue Skies for all!!

Tiffoso

RE: Sig Smith Miniplane
 

Hi Tiffoso,
Do you have any photos of your new SMP? I'm trying to figure out how Iwant to setup my fuel tank and lines. I plan to cover mine with Sig Koverall and Stix it but don't have a color scheme in mind yet.

RE: Sig Smith Miniplane
 

Here's an idea for you:

RE: Sig Smith Miniplane
 

Hi Bipes,
I can't get your photos to expand to full size but from what I can see your SMP looks groovy!http://www.rcuniverse.com/forum/js/f...sn/thumbup.gifGreat shade of blue. What did you cover it with?
Dave</p>

RE: Sig Smith Miniplane
 

Helo, Gentlemen...TCraft Lover, I have no PhotÔs right now, just those in my page...feel free to get a look at then...I`ll get more as soon as I can buy a new camera (photo cameras dislike wine... :( ).

Besides...I believe in free of mind when it comes to finishing your work of art, and believe me...finishing a Smith...Oh my...is sometinhg like finishing something no one has ever done before...at least thats what I felt. :)

Do as you please..do as you feel is up to your satisfaction...

Never mind comments, likes or dislikes...it`s YOUR PLANE. EXPRESS YOURSELF!!!

That`s how we do here in Brasil...and some does like what we do down here.. :D

The looks reflect its maker...think of it!!!

Do your best, f... the rest!!!

And post a few pics if you can...

Blue skis for all!!!

RE: Sig Smith Miniplane
 

Hey Tiff,
I dig your attitude man. Rock on! http://www.rcuniverse.com/forum/js/f...ades_smile.gif

RE: Sig Smith Miniplane
 

I can't take credit for them. They are pics of the real Bipe.

I believe the blue is actually grey.

I found these pics on another Smith Miniplane thread lurking around RCU somewhere.

Brian

RE: Sig Smith Miniplane
 

Oops!! http://www.rcuniverse.com/forum/js/f...ssed_smile.gif

RE: Sig Smith Miniplane
 

Planebuilder66, that is a beautiful Bird!!!! great job! I just this minute recieved my Smith Mini Plane, it is a true Vintage kit at least 20 yrs old but the plans are in great shape if a little yellowed... the decals are good too. I built one with a friend about 12 years ago and we powered it with a Saito .50 4-Stroke and that was plenty of power!! I have an OS .48 Surpass but I am thinking of a Saito or OS 4 stroke of around .60 size for this build, it has to be a 4 Stroke.I wont start it for a few weeks but I am watching this and the other SMP thread for input. I might have mentioned it before but our beautiful SMP was crashed by a friend of ours hard in from about 25 feet up inverted, pulled up elevator right after saying the now famous "Airplanes aint *****" well let us just say that he hears about it fairly often... I wont let my friend fly this one.[sm=shades_smile.gif]

RE: Sig Smith Miniplane
 

HiTif,You are right about one thing, we should all be proud of what we make- no matter how it turns out. Whether it is an aeroplane, dolls house, whatever, you should stand back and say yo yourself "I made that".
I have recently built a model of the round the world yatch Volvo Open 70 Extreme. 3 foot overall lenght 6 lbs, radio controlled. winch sales. extensive rigging. I sail this with my local boat club. After making it Istood back and proudly said to myself "I made that"'.That is what modelling is all about.The smp can be difficult but boy do you feel happy when it is finished, even if the engine does drop off!

Just for those who think "who is this guy". Before joining Xerox ,systems &amp; applications div. in 1965. I am still with them, I spent 21 years in the aircraft industry working for Sir Frederick Handley-Page on the Halifax [ bit scary that was, we only took one bomb hit , no one hurt, and Victor bombers and HP Hastings transport plane, which incidently I serviced as a Leading Aircraftsman, on the Berlin Airlift, wow was that a tough assingment. The Germans loaded the coal! while I was with Sir Fred he asked me to model the Victor bomber for his boardroom. This I made in clear perspex, including laminated wings and drop off nose. To this day it is a trophy [Handley Trophy] for an inshore sailing club that I used to belong to.

Happy building and stand proud! Glen. ps, It is B......... freezing. Time for tea!

RE: Sig Smith Miniplane
 

Hi Daddy, The Smith Miniplane is currently available here from , www.pegasusmodels.co.uk @ &pound;122.oo. I may get another before they go, they are not in stock for long. . [I have had my cup of tea ,bit warmer now.] Glen.