2.4ghs

My Feedback: (15)

Mine would do the same thing in the loop, I decreased the elev. throw and had one elev. just slightly higher on the up fixed that and decreased my throw and problem when away. You should be able toget aleast one and a half loops with full up elev. before it would try and snap out. I can go into a loop and pull all the way and the loop would just get a little tighter.

RICKSTUBBZ

I loved doing a Lomcevak (at least a simulated lomcevak) [8D]with my “Smith”. Most time I cheated at how I got into the maneuver.

The proper way in, so I am told, is from a 45° knife-edge up line. If you are on the right side ... jam in all of your left rudder – full right ailerons and full down with lots of throttle.

I usually went into it from a quick 45 ° upright up line-simultaneously cut throttle to about half-jam the sticks for a inside snap (full up, full right aileron, full right rudder) Then trying to time one half a snap –jamming in left rudder (from right), full throttle, full down (from up) leaving ailerons at full right.

If all goes well you will get the coolest tumble (at least before 3D came around) you ever saw. The plane seams as though it stops moving and the tail simply flips over the top and around as if the thing was thrown like flicking a twig.

Another thing this plane looks cool doing is a old fashioned tail slide. But, it is hard to hold you mouth right to get it to work..... I was successful at getting a few slides that were good for at least 10 foot or so. I needed to have pretty much no wind to pull them off. It just looks so cool falling strait down with the nose pointed strait up.

RICKSTUBBZ

Rv7garage

My Feedback: (10)

Hey Rick- yeah, I've changed my RCU handle a couple'a times since '06... Finally got the one I wanted! You can just call me Paul, if you wish

dorona

OK guys some help is needed here...
I am at the stage of building the bottom wing ailerons hinge.

the plan showa the section of the hinge which is not 90 deg.
the wire rods i hve in the kit (including the bearings on them) are 90 degrees.

can someone share the right way to do this? also some pictures will probably help a lot.

thanks

doron

hinam

Hi Doron!
Try flipped through [link]http://hinam.ucoz.ru/photo/6[/link] here, that may be - you see something useful for themselves

rc_wings

Hey Doron,

The hinges are correct as per the plan, and should be off 90' in order to get sufficient wood to hold them in place. As for the torque rods, you may want to consider not using them and instead, mounting a servo in each wing half. Will be much cleaner and provide more flexibility in setting up differential through programming rather than mechanical. Assuming you have a spare receiver channel. If not you can always use a Y-harness. If you need some examples, I can share what I did if not already a few pages back in this thread.

Just got back from vacationing in the woods with the family. Hoping this week to get a little more stick time on the SMP.

dorona

Marko hi. No problem adding another channel in my receiver.

rc_wings

Hi Doron,

Here are some pictures of SMP aileron mod. Unfortunately I did not take more detailed shots during the build, but it should give you a good idea of how it was done. I cannot take any pictures now, as I covered right over the hatch doors, hoping I would not require access for some time. When the day comes that I need to get at the servo, I can simply cut the covering around the door and pull off the door, do what I have to do, then fix up the covering appropriately. Would not recommend this practice, unless you are 100% sure you do not need in after covering. Spending a little time to cover the hatches properly for easy access is well worth it....unless you are lazy like me and gambled I would not have to get at the servo any time soon. You have to admit it does look clean!!!!

There are many ways to mount a servo in the wing. You can even mount it to the hatch door itself. I typically never do that, but is quite acceptable. I mounted mine inside one of the ribs, with a ply doubler for servo mounting reinforcement. Then lined the ribs to accept a hatch door neatly inserted. You will need to use a smaller profile servo to fit in the wing as a standard servo will not fit as I recall.

Let me know if you need more details......

rc_wings

post in error

dorona

[img]C:\Users\doa\Desktop\SMP pics\IMG_2821.jpg[/img][img]C:\Users\doa\Desktop\SMP pics\IMG_2820[/img]
Marko hi.
Thanks for the tips, I will surely consider to mount the servos in the wings.
I have to admit it does look very clean and nice.

Just to verify it was not me who didnt understand: the picks show that the torque rods in the plan are not 90 deg and the ones I got in the kit are... right?

(i added 2 pictures to demnstarte)

Thanks in advance
Doon

rc_wings

Doron,

The plan does indeed show the torque rods at an angle greater than 90 deg, and the ones that came in my kit are just slightly over 90 deg. You should be able to bend them to the angle required. I don't think the actual angle is critical, as long as both sides are lined up and you get the required travel in both directions. You can "twist" the rods to get more or less angle as required. One end in a vice and the other end you can grab with a pair of pliers then twist. After drilling the holes in the ailerons for the torque rods, check the fit and ensure both sides line up in the center with ailerons on, prior to applying any glue. It will be difficult to twist them after they get mounted.

Once again, I abandoned this method and opted to use dual servos - one in each wing half. Another idea I toyed with was to use the torque rods as per the plan, but then mounting two servos side by side in the wing center...one for each torque rod (aileron). This would give you the individual aileron control, and prevent having to modify the wing for mounting a servo. Anyways...some ideas to ponder over.

BTW - The pics you attached do not seem to display.

Cheers,

rc_wings

Had the little SMP out tonight for a couple exhilarating flights. This little plane is slowly becoming a favourite. Have a video I took on a small point and shoot camera, mounted on an old cap....call it my CapCam. LOL. A quick fix to not having a person to do the filming for me and cheaper than a GoPro. Little issue with my ISP in trying to upload to YouTube, so will try next week from work. Really enjoying this little plane!!!!

RICKSTUBBZ

Marco,

I'm looking forward to seeing the video from the Cap Cam. Glad to here you are enjoying your Smith. I like your discription - exhilarating! [8D] The Smith is capable of as much exhilaration as you want. Yet....will tame out for some nice scale flying and touch and go's....

dorona

Marko and all.
I would like to share with you guys some of my building picks.
Tried to do it last week but the photos would not show...

how do I upload pictures to the forum?
Is there a limit of size or quantity for that?

also
When looking at the plans, it seems that in order to mount the Ailerons servo i need to cut through the main spar of the wing. Is this what I really do?

Doron

EF

Hi Doron,

In order to upload pictures you need to 'Reply' to a particular message.
You will then see at the bottom an option to upload files/pics.

Re your question on the aileron servos - why not use what is shown on the plan i.e. a central servo driving the ailerons via torque rods?
IMO it's the lightest and cleanest installation and after ~8 years flying with mine, I cannot fault this setup.

senrak

I agree with EF on the aileron arrangement. This plane isn't large enough to warrent the need for the extra servo power. The bad thing is the extra weight it adds to the air frame becomes burdensome on it's performance.

Dorona. You never cut into a wing spar.

EF

Actually the plan shows you do in this case, in the center section.
For that reason I assume they provided spar doublers, and the whole center section is sheeted.
If you have the plans for this model, check the cross section that shows the aileron servo installation.

On my model I moved the aileron servo aft a little in order to avoid it, but that is just a personal preference.
The plan shows otherwise.

rc_wings

I used two mini servos, one in each wing half and combined they weigh less than one standard servo......so weight should not be a concern. Using dual servos allows for easier setup and adjustment of differential, which this plane requires. Much easier than trying to do this mechanically, and even better if you plug servos into separate channels on the receiver and can avoid a Y-harness. Using a computer radio, adjustments are a quick and simple task. The other reason I used dual servos, mounted approximately centre of the aileron, is to eliminate any "twisting" of the ailerons that typically occurs with torque rods. Mounting the control rod mid way will distribute the load evenly on both sides of the aileron.

Agree it is simpler to just do as per the plan, and nothing wrong with that method, but will make adjustments much more challenging later down the road. Keep in mind this plane was design well before computer radios and compact servos, so the method of using dual aileron servos was not practical back then. Now it is a feasible option and a great modification to this kit IMHO.

Doron,

As per the plan it does show that the spar would need to be cut in order to mount the servo. I would NOT recommend mounting it where it calls for in the plan and cutting the main spar (VERY BAD!!!!), but move it down slightly behind the main spar as per the picture EF has posted.

Cheers,

RICKSTUBBZ

Just for the information.....because this plane is small......... you can use smaller servos for the ailerons, if you are using two servos. It is possible to get two metal gear sevros with plenty of strength that will actually weigh less than one standard servo. So, two servos can be done with a weight loss.[8D]

I would certainly locate the servos where you did not have to cut the spar.

For the record I built my Smith with one servo using bellcranks and it worked flawlessly for years. Albeit the set up had a little more slop than a two servo set-up.

EF

I twisted both the torque rods backwards a little in order to have differential ailerons with my single servo setup.
It doesn't need much (or maybe any at all?) as it has a rather low aspect ratio wing(s), but a little diff never hurts.

BTW the main reason I moved the servo back was since I thought it could free some space above in the fuselage (later found not really necessary).
I would not be too concerned about the wing's strength since the upper wing and N struts do 'close' the structure to a very strong 'box', plus it is a rather small model to begin with.

rc_wings

Just the thought of cutting the main spar concerned me when I was building mine. What I put my little SMP through, I am glad I did not as it needs every bit of strength possible to keep those wings together and on the plane. She is no 3D'er and I did not expect it to be....but man am I having fun with it.

rc_wings

Here is a video of the SMP in action. Was recorded on my little point and shoot camera mounted on the rim of an old ball cap...call it the Cap Cam. Was more a test to see how it would work as never seem to have a reliable camera operator handy. Now that I know it works, will try to get some better footage. The SMP is pretty fast, so going to change the prop from a 10x7 to an 11x6 and see how the Tigger .51 handles it and should slow the little Bipe down a bit.

http://www.youtube.com/watch?v=mrKbLFC74_k

Marko

EF

I use a 12-6 APC on an OS 46 FX.
Plenty of power (almost unlimited vertical) but can be flown very slowly too in a nice scale manner.
Also allows good slowing down on the approach.

RICKSTUBBZ

Marko,

I watched the CAPCAM video. It turned out better than I would have imagined. That is cool. Now if you could just setup some kind of zoom control. Is the spacewalker yours too? [8D]

If you get a chance - try a 12X6 prop on your ST51 and Smith. I am pretty confident you’ll find it to be a good combination. Here is some info I have put together over the last few years on the ST51. When reading this keep in mind I use home made no nitro fuel. In fact my fuel is quite simple 19% sig castor oil and 81% methanol.

This test done 7/11/11 was performed with the engine in a Tower Hobbies Uproar and is only showing rpm’s with out all of the details of the write up. To summarize the write up I did - the 12X6 (reference being a wood prop) is the go to prop on the ST51. If your looking for speed 11X7.5 is great. The lower pitch props tend to increase the prop torque or “P” factor effect noticeable.
12X6 Zinger 10,300-3400idle
12X5 Zinger 10200 - 3820 idle
12X4 Zinger 11,800 3850 idle
11X7.5 Zinger 11,000 3500 idle

My results were the same on my Smith. I even tested the Smith with a 13X4 and even though the speed was perfect, the torque generated from the hi thrust could make the little Smith a bit more squirrelly than I liked in a given situation. I think I wrote about some of that in this thread somewhere.

In a 02/19/09 test I had one of my Super Tigre 51’s mounted in a home made engine test stand that I could measure thrust on. Again, FAI fuel....

02/19/2009 - temperature 76° - humidity 53%

Prop_ _ _ _ _ _ _ _ _ RPM_ _ _ _Thrust in lb/oz
10X8-3_ _Zingalli_ _ _ 11,000_ _3-8
10X6-2_ _MA wood_ _ _13600_ _4-4
11X7-2_ _Zinger_ _ _ _11150_ _4-1
11X7-2_ _Top Flight_ _ 11250_ _4-10
11X7.5-2_ _Zinger_ _ _11000_ _4-6
11X7.5-2_ _MA plastic_11310_ _4-10
11X8-2_ _APC_ _ _ _ _11200_ _4-5
12X4-2_ _Zinger_ _ _ _11750_ _4-12
12X5-2_ _Zinger_ _ _ _10500_ _4-12
12X6-2_ _Zinger_ _ _ _10650_ _4-14
12X10-2_ _Zinger_ _ _ 7000_ _2-14
12X12-2_ _Zinger_ _ _ 7000_ _2-15
13X4-2_ _Zinger_ _ _ _10100_ _5-3

Having a heck of a time making this chart look right hope it reads better now???