Wing Folding Mechanism

Hi San2ndjune,

You might check out U.S. Naval aviation sites such as this one. Carrier based planes use folding wings to save valuable space.

Regards,

-John

I built a catapult launched model glider that worked in a manner very similar to the one you are proposing.

The starboard wing used the threaded neck of a plastic soft-drink bottle (male threads) and cap (female threads). The coarse thread provided enough vertical movement in 90 degrees of rotation to allow the thin foam wings to move from an overlapped position to one of equal height.

It should be noted that subsequent gliders were built without this feature, and there was no discernable difference in the flight stability quality.

They looked funny, though, with one wing higher than the other.

Do you mean something like this? The hinge on the wings are parallel but at an angle to the plane. When you fold them, they're not on top of or touching each other.

this is the simple line diagram of the problem. Wing hasto open from the Botom position. Above fig shows fully open condition.Fig below shows unfolded condition. Both the wings will be hinged at center line of the fuselage and at offset. so after opening both has to come at the same level.

Dear Friend,

I am also looking for a reliable wing folding mechanism for a glider which is in flight. For eg dropped from an aircraft. Some mechanism should release the folded wings for deployment. May be a trosion spring, when the folded wings are held in place by a latch which can be released by a solinoid. Or wings can be released by some pyrotech mechanism or---- or----. Can we exchange more notes on this technique.

Thank you

James

e mail : jamesvarkey52@yahoo.co.in

Hello James,

As you explained ur problem is that u have two split wings which is kept folded inside the fuselage at an offset. So while deployment wings are required to be rotated during deployment and also required to be co planner . So two motions are required;

1. Rotation of wings (Which can be done by using connecting rod and pyro cylinder)

2. Translation of one wing or both whichever to make it co planner.

our major portion of problem is the 2nd one means translation of wings.

Did u have any idea or rough concept about 2nd one?

Regards
Sandeep

Dear Sandeep,

My plan is to have two wings sitting one over other and when released it simply spread to sides. No rotation required. Only one motion is required sideways. One approach is, each wing is held by torsion spring and when the locking mechanism is released, just spread to sides and locked at 90 degrees. What is your views on this?

James

I had a look at what was suggested and i am asking myself if i understand correctly your specification:"There is a wing which is split in two halves so that it can accommodate in the fuselage(cylindrical)."

You got suggestions about solutions "over or around the fuselage but not "in the fuselage". Am I right or not?

If i am right what you need is a kind of "scissors". Now what power do you intend to use for unfolding? Human, electrical, hydraulics? In the assumption that you need -as i think - a folding "in the fuselage" the solution is : an actuator generating a linear movement in the plane axis and 2 connecting rods to the half wings. The connecting rods are on their other end bound by sleeve bearings to the half-wings at a distance to the central pin (or to the pins connecting the wings to the fuselage so that when the actuator extends the wings open and when the actuator retracts the wings fold in the fuselage. The displacement along the pin can be done either with a "thread" or with a secondary connecting rod using the cosine -effect.

The same principle but much more complex is used to change the wing form in under or over sound speed travel for military planes.

If you need more help then give you mail for a direct contact.

Thanku very much for ur reply. What I understood from ur reply that u want me to use one linear actuator and a scissor mechanism (connecting rod). But for opening this will work. But in unfolded condition the wings are one over each other and at offset, so while opening one wing has to come down or go up to come at the same level.
I have tried some link mechanism. I am thinking about some electrical portion also

Sorry to react with such a delay but i do not know why i do not get any more automatically the news.

I am aware of the deplanation problem. First it will be better if the 2 wings will have a combined displacement since the amplitude for each one will be half of the whole. I mentioned two possibilities: 1- use of a ramp (as a square thread) so the rotation is automatically combined with an axial displacement or use a secondary connecting rod with spherical ends so that when the wings turn the rods either pushes upwards or let it come down wards. Any way which ever solution you choose it is compulsory to lock the wings in the end positions. I am glad that i understood your question the right way and was able to suggest a solution according to your need. When you design the actuating system you can use several energies for the operation depending upon 2 factors : the time you accept for the operation and the weight of the wings. Since the folding/unfolding has to be done before the plane takes off it is better to use a NOT on board power source as for instance the power of the electric system of a car. If time is not a constrain then an operator powered system can be designed. You can accept that an operator can supply for a short time up to 80 Watt in turning a handle. If you want when you are so far i can have a look at your design and may be make some suggestions. If you want to have a direct contact then give me your mail so that we can establish the link.

For the choice of your system principle you should take into consideration also the actuator mass. For a given force a hydraulic system can be the optimal solution but only from this point of view.In the case of an electric system it is better to have a fast running motor with bigger reduction since this combination is lighter than a stronger motor with a lower gear.

Take into consideration as well the fact that with only one shaft for both wings there must be a possibility to assure a symmetrical movement if not there is a risc to open fully one wing and the second first partly and only when the first is at stroke end open the second full.

Is this what you wanted? The wings pivot and fold back over the fuselage?

This is a model of the TBF Avenger, a torpedo bomber from World War II. There must be a hobby shop you can get this from. A good one would have the ability to fold the wings and that might give you an idea.

I am assuming the glider is to be launched using a tube (cylinder). You might consider using a different form of wing folding. See my patent for the Sling Wing, #4,836,817. I experimented with 'quite a few' different folding wing designs before settling on this one, it follows the KISS principle the best of any I tried, and that is very important in any of the aeronautical disciplines.

A spacer, in the form of a tube, can be placed between the two wing halves, to allow for a fuselage. This tube passes through a larger tube in the fuselage, after the wings deploy they will assume the proper incidence angle, provided you use a pitch stable airfoil.

Some time ago i suggested a solution and i would appreciate to know if it helped.

There is an other approach with 2 shafts making an angle with the final open wings plane so that automatically the wings come one above the other when folded.

If you want more details on this, i think, more safe and very simple solution say it