Props4ever

Hi Byron,

Currently i'm experimenting flap system that ampbomber used on his 3 bombers to see if it works for me, i can see it workable but i have to rig it up for my model's needs. If his system didn't worked then i will go back to my original plan and use Garolite and see if that does the job. I wonder if i can find it here in Toronto somewhere, hmm .

Yes Nose gear is looking really nice, i can't wait to get it and test it now. My friend is doing excellent job on it.

Hey stuff happens to all of us at times, well this hobby is the way to relax yourself from the stressful lives we have out side of it...least it's that way for me.

Its nice to see you posting on here again!..

FliteMetal

Below is video of George's Tu-95 Bear bomber flap mechanism:
http://www.youtube.com/user/ScaleAero


Top side View: http://www.youtube.com/watch?v=wRcnDv8tlU0

Bottom side View: http://www.youtube.com/watch?v=vpluvzmBmoA

Single Center Flap Servo: http://www.youtube.com/watch?v=mtzqAI6md1Y

Props4ever

Hey these are great videos George, thanks Ed for linking them on here.
This is cool set up, i just hope i could adapt this into my model.
I am trying to find how many types of sail servos are currently available and who manufacturers them currently!. If i could get it in standard size then i'm in luck
as i am really leary to use 1/4 scale servo in all honesty.

bentwings

I used to use the 1/4 scale servos in my Corsair for flaps as there just wasn't anything that big in a standard size servo. Futaba 134 I think. I eventually went to the big JR 4 oz behemouth. That one was pretty tough. It survived a flap down gear up landing in the grass/weeds. I still have one in the P-51 for the flaps. Works great.

edit

It has 139 in/oz torque and .28 transit. You will need the heavy duty DuBro arms.

bentwings

I should probably kick in here for what it is worth as we are building a big 118" twin engine bomber B-25. This has inboard and outboard flaps that are pretty big area wise. They are 50 deg down capable but 45 will be the normal flaps down angle. We have gone thru about 1/2 dozen JR servos trying to get a perfect combination. The problem is to first get 2 servos to work together. It is difficult to get the angle of the arms exact so both inboard flaps go down the same rate and finish at the same point. The next thing is to get both inboard and outboard to go down the same rate and distance. We've given up on getting all 4 flaps being at the exact same position and settled on getting them matched side for side. I'm at the point where the JR 'matchbox' is going to be the only way. I'm not even convinced that it will work. We've got more $$$ in flap servos than a lot of guys have in their whole flight operation. haha We have 4 $120 digital servos in the wings now and they don't work any better than the 15 dollar servos do. With a 10 channel radio we can mix about anything we want and we still can't get 2 of the dang things to track together. I hate to take one apart and tweek the servo pot which would probably solve the problem but it just leaves you wide open for future problems. We are almost to the point where we will convert the inboard flaps to bellcrank drive and use just one servo. It will be a lot harder to do this with the ouboard flaps as the majority of the OB flap is in the outer panel. Mechanical linkage is pretty much out of the question. We even designed the linkage on Solid Works and made all the parts together.

I sure would hate to have to program a mix to counter roll when the flaps go down. Funny thing is that I never really gave it much thought with the Corsair. Yeah I measured it but half flap was definitely not the same side for side and the plane never rolled a bit. I even used 1/2 flap for manuvering at times. It appears that 5 deg off isn't such a big problem but I really don't want to fight the plane on the maiden flight.

As big as your flaps are and as much as they will affect landing, it is something to think about. Just my dollar....inflation you know. haha

FliteMetal

According to George...the Futaba sailboat servo has worked out perfectly.
These are pretty easily found and mounting the flap using either arrow
shafts or carbon fiber rod with stops to force the flap tilt as the push rod
continues rearward is about as simple as it could get...as you can see in
the posts describing more complex systems.

I view flaps with respect to your project as a cosmetic feature and not so
much an element of control. I'm simply guessing, but 20 degrees on that
wing should have a decent effect on your landing approach.

The fiber glass arrow shafts will slip over an aluminum shaft as well for a
good slip fit that would need minimum lubrication.

ampbomber

My Feedback: (7)

Try and remember that I only use one 150 oz/in servo to drive both the right and the left flap and that drives both at the same time. I did modify the sail servo ( it's proportional) for 180 degree rotation so it could be slowed down with the Tx.

Props4ever

Ed, Yes i know what you mean as George's perfect set up using sail servo, i personally want to
use standard size servo as it will save bit of weight and space too. On another forum one guys is saying
any servo could be programmed to do this if i buy servo from servo city and another fellow is saying servos
doesn't need to be modified as this could be done with computer on the transmitter. Now what do you guys have to say about this.
I will be using Multiplex Royal Evo 9 with either Multiplex Rx or Futaba Rx.

As for flaps on my model, i doubt its only cosmetic since i have scale airfoils on this wing with 1.5 degrees on incidence.
I am sure due to scale airfoils there will be good amount of flaps needed as 20 degrees may not be enough
but we will see once she is air born.


New updates are coming very shortly on the nose gear assembly, stay tuned. [)]

FliteMetal

The gearing of the winch servo is what you are after. The derived torque permits the servo to over
come stall which will occur at a different rate if less than appropriate servos are utilized for flaps.
The additional increase in wing cord/area alone should contribute to a slower decent to base leg
and final to touch-down.

If you are not careful, you could end up with "a" working servo and others which stop working as
they are stalled during use. A winch or tillar servo is purpose built to permit a larger than normal
load distributed across a gear train acting like a multiple segmented hoist to achieve mechanical
advantage for load bearing in addition to the smooth motion across a large sweep angle. You are
in fact creating a block and tackle function.

The fewer components to the flap functionality tends to provide the best solution with the least
amount of maintenance. This is not a put it in and "forget it" component of your airframe. Using
two winch servos driving 180 degrees out on two flap sections isn't what I would call a stretch
based on the almost 50 degrees of George's flap. True George's are less area on a lighter plane
but yours can be twice as high since two servos would be used instead of one. Driving outside
flap section on each wing with 1 servo, and driving the inside flap section with another is what I
am talking about.

Props4ever

I like you guys to see the track and slider that i designed for this set up as my final design, i am not sure it i posted these images in past posts but here it is once again.

This is single slotted track and 2 guiding pin slider that travels in the slot. Image shows movement of slider in the track.
When i designed it, i made small added section on the L/E of the slider so i could attach linkages to it but now after seeing how George did his, i will most likely be modifying that
frontal added section of the slider. I will be posting more pictures of this wooden mock up in the flap bay for you to get better idea.

Props4ever

You mean something like this Ed.

http://www.rccanada.ca/rccforum/atta...3&d=1168618612

FliteMetal

Two of these...one for inborad and one for outboard "pairs" of flaps...
http://www.youtube.com/watch?v=mtzqAI6md1Y

ampbomber

My Feedback: (7)

Sammy, I'm still confused about your flaps. I thought you had said that each side was one piece. Please post a picture of the bottom of your wing.

Props4ever

Yes each wing has 1 flap on it..

Props4ever

Right flap bay. You can also see first few mock ups i made of tracks and sliders.

Props4ever

Ok now i know what you mean....Don't worry about above link i posted earlier Ed. George sorry for the confusion.

Props4ever

I'm now posting bunch of pictures which my couple of friends took for me recently and now i finally got them.
You guys will see most of the progress i have mentioned as in text form in earlier posts but now you will pictures of those areas.

Props4ever

Some more with flap bays showing also, right flap has been opened up but left one is still solid.

Props4ever

Flap mock up in various stages of replicated operation in the right flap bay.
Last picture was taken from left side to show the slotted track.

Props4ever

Pictures of my mock up version of strut that a friend from TAM helped in creating. This was the hard time as NO large enough strut could be found in the market and didn't knew another friend will actually build scale nose gear assembly for me.

I used aluminum 5/8" tube for outer body of the strut and 1/2" stainless steel rod for inner oleo strut portion. Axle was 5/32" that i epoxied to the bottom of the oleo strut.
Wheels are 2-1/4" Dubro straight tread wheels, i didn't had access to wise to bend the axles into canted position.

FliteMetal

I confused you in my statement about inboard and outboard flap sections.
Each servo would drive a separate flap.

Props4ever

Yep Ed just a bit, I was thinking to use each individual servo in each wing but George said, it will be too complicated plus i would need huge servos arm to push out and pull in 3" spacing.
Therefore i think its best to use his set up utilizing one servo in the middle of the wing and then running 2 Nyrods or cables to each flap on either side. I know trailing edge of cut out flap bay has sustained bit of hanger rash but nothing that could be fixed with foam.

I'm pretty sure that his set up will work on this model. I will keep you guys updated with the progress.

FliteMetal

My reasoning for two (2) servos is the area of your flaps compared to that on the Tu-95.

ampbomber

My Feedback: (7)

Ed, actually we compaired the size of the Tu-4 (B- 29 clone) to Sammy's Connie and I believe we found them to be about the same size. Each flap on the Tu-4 is 3.5 x 31 inches, plus the inboard 7 inches is 4.5 inches wide. The Ttu-95 is a bit more complicated due to the flaps being split by the IB main gear housing. The Tu-4 uses an older Futaba 9602 sail servo 130 oz/in (at 4.8V) and was difficult to disassemble to modify but the Tu-95 uses a Futaba 3802 152 oz/in sail servo ( at 6V) and comes apart easily for modification.

Props4ever

These are in-line pictures of inboard nacelles including outer ones too. The purpose of posting these pictures is to show working area between IB nacelle and flap bay where track and slider will be mounted in the bay.