Author Topic: New Hard Point Exponential Handle design (Read 10995 times)

Larry Renger · « **on:** April 27, 2016, 09:23:14 AM »

As mentioned (often) I am a fan of exponential control handles. There was valid criticism in another thread that my current design has too much "overhang" and that makes the controls need a heavy hand. This limits the usefulness to rather light models.

Challenge accepted!

See the attached .pdf for my new low overhang version. The goal is to have the spacing hit maximum slightly wider than you would normally space the lines and slightly less when at neutral.

Now, before finalizing the design, I need some input from the assembled multitude! What is the range of handle line spacing in common use? Please tell me what you guys actually use.

Thanks!

Gerald Arana · « **Reply #1 on:** April 27, 2016, 10:04:39 AM »

Interesting idea Larry. Let us know how it works out for you.

Tight lines, Jerry

Andrew Tinsley · « **Reply #2 on:** April 27, 2016, 10:20:31 AM »

Hello Larry,
My line width is usually around the 4 inch mark, but then I am not a very good pilot!
I think it seems to be a very neat idea. One that is obvious once you have seen the drawings! I am not quite sure why you have gone to the U shaped swivel pieces, maybe a thick oblong would do the job? Now tell me where I am going wrong! Oh yes, it allows a much wider line spacing if necessary! The idea is just great!

Andrew.

Tim Wescott · « **Reply #3 on:** April 27, 2016, 12:06:07 PM »

I've gone as low as 2", but (A) I tend to use less spacing at the handle than most people, and (B) the plane had problems that I since corrected. I certainly go down to 3" regularly.

Steve Helmick · « **Reply #4 on:** April 27, 2016, 04:42:39 PM »

Typically, I try to get to 3" plus. It looks like this handle is just a bit too wide for my current planes. Would love to try this handle; the sooner the better! I assume the "U" fittings would be stout enough for a 45 lb pull test? Titanium?

Steve

Brent Williams · « **Reply #5 on:** April 27, 2016, 05:16:51 PM »

Garolite, G10, FR4, are good materials that are readily available.
McMaster Carr has them in suitable thicknesses.
It will kill saw blades. Use a fresh drill bit.

Larry Renger · « **Reply #6 on:** April 27, 2016, 07:17:38 PM »

Quote from: Steve Helmick on April 27, 2016, 04:42:39 PM

Typically, I try to get to 3" plus. It looks like this handle is just a bit too wide for my current planes. Would love to try this handle; the sooner the better! I assume the "U" fittings would be stout enough for a 45 lb pull test? Titanium? Steve

I think that 3/32" steel will do nicely!

The handle can be bigger or smaller, which is why I need to know the typical range used by a wide range of pilots. It would not be hard to have larger and smaller versions since it is just a matter of putting the correct file into the laser cutter. The links stay the same.

Steve Helmick · « **Reply #7 on:** April 27, 2016, 07:56:10 PM »

Quote from: Rusty Pieper on April 27, 2016, 05:32:01 PM

Are you trying to beat the hot rock handle?

That's been done a couple of decades ago, with Ted Fancher's hardpoint design. It is a kit, so you can make it fit your hand either like a Hot Rock, or whatever you like, whichever comes first. Plus, it discards of the cables and their potential for breaking at a bad time...ask Howard! But if you like the Hot Rock and disregard something that's MUCH better, go right ahead.

Steve

Larry Renger · « **Reply #8 on:** April 28, 2016, 09:54:59 AM »

(except I can't find a decent 1.5 square battery.) quote

I remember seeing a fake battery that took 4 D cells inside. Would be way better than the original, but look right. Don' remember where, sorry.

bill bischoff · « **Reply #9 on:** April 28, 2016, 11:41:48 AM »

(except I can't find a decent 1.5 square battery.)
Tower Hobbies HCAP0700 $5.99

George Albo · « **Reply #10 on:** April 28, 2016, 03:50:39 PM »

Quote from: Rusty Pieper on April 28, 2016, 09:12:41 AM

Yes, I am locked into old school. Vintage. Why have a vintage plane with a modern engine, carbon fiber bell crank, a scientifically designed handle and modern engineered prop? I have to decided to be a complete vintage flyer, with all items being era correct. (except I can't find a decent 1.5 square battery.) I do have the white Top Flite and wood props that are date correct, though.

Seriously, I am glad a equipment advantage is being sought. I have seen people use what I got and fly 10x better than me, so at this time I know the improvement needs to be me, not equipment.

It looks nice. I hope it works out.

Here. See if this site has what you need. http://www.radiolaguy.com/Batteries/Vintage_Batteries.htm Make color copy and epoxy to existing battery. I'll be making an EverReady 1.5 volt linemans battery. Collecting materials to make including knurled brass line connector. Will post pictures when done. Have fun. George Albo

david beazley · « **Reply #11 on:** April 28, 2016, 05:35:54 PM »

Here's an old thread. I made a couple.
http://stunthanger.com/smf/open-forum/replica-dry-cell-battery/msg386461/#msg386461

Larry Renger · « **Reply #12 on:** April 29, 2016, 05:33:45 PM »

Come on guys, I need all the input on average, actual use line widths I can get. I would really like to only do this once!

I think these handles could work well for many people, but if I get the spacing wrong, it is a waste of time and effort!

Work with me here.

BillP · « **Reply #13 on:** April 29, 2016, 06:32:52 PM »

I fly large and small hot rocks and the 4" small is my preferred go to handle...but would like to try 3 to 3.5".

bp

Howard Rush · « **Reply #14 on:** April 30, 2016, 05:45:38 PM »

What are those squares on the side of the handle?

Larry Renger · « **Reply #15 on:** May 01, 2016, 07:24:24 AM »

Those are cut out areas to reduce the handle weight.

Carl Cisneros · « **Reply #16 on:** May 01, 2016, 12:25:16 PM »

Larry

as drawn,the handle would suite me to a treat. I have 3 planes that use the 3 1/2" spacing and 2 with
the 4" spacing to fly and feel comfortable with.

I like the idea of being able to adjust the width using the bolt locations.
The only thing I wouldlike to see would be some way to actually do minor line length adjustments especially from switching
from one plane to another. ( I know, we all should have a dedicated hanlde per plane. )

Also, one other thing yours has that the others do no have (from what I have seen as least) is the hole for the
wrist lanyard. Excellent thought.

Carl

Larry Renger · « **Reply #17 on:** May 01, 2016, 01:24:31 PM »

If you have adjustable line length built into the handle, you end up with some angular bias that changes the rate of inside to outside maneuvers.

This handle is designed to be used exactly at right angles to the lines.

I finished making the links and am awaiting the laser cut wood parts.

Allan Perret · « **Reply #18 on:** May 01, 2016, 04:31:28 PM »

3.25" at neutral with the links in center holes.

Curare · « **Reply #19 on:** May 02, 2016, 12:49:15 AM »

Larry, considering you've been fiddling with expo handles for the little stuff for a while, maybe you can tell us of the difference in feel?

I'd be expecting there'd be a resounding clank come through the handle on eights (inside to outside)?

Larry Renger · « **Reply #20 on:** May 02, 2016, 08:36:46 AM »

I have "Essential Familial Tremor", that is, my hands are very shakey, especially when I try to do something precise. As such, the exponential handle helps me fly smoothly at level and round maneuvers while giving the kick needed to do square corners. This is especially important with responsive models such as we fly in 1cc (1/2A metric size).

I have never noticed any "clank", nor has anyone else who has tried the handles. Jim Hoffman recently borrowed one of mine, and promptly ordered one for himself. Perhaps he will comment?

Jim Hoffman · « **Reply #21 on:** May 02, 2016, 11:43:37 AM »

I borrowed an Expo handle from Larry in March and did some trials on a very good flying Ringmaster. I found a subtle but interesting change in the feel of square maneuvers. I also measured the Expo handle and found it had overhang 1 inch greater than my normal handles. This added overhang will increase the control loads one feels at the handle and would likely not be happy for me on a larger stunter. This is what prompted Larry to create the “lower overhand” design he shared at the first post on this thread.

I put together my own handle and have attached some photos. This is an earlier generation handle than the “low overhang” Expo Larry shared in this post.

Notice how the handle operates; as you come off neutral, one link rotates outwardly to oppose the reduced spacing that occurs during handle deflection. I hope to do some flight trails this week on both the Ringmaster (26 oz.) and a slight larger OTS Galloping Comedian (35 oz.). I have a 45 oz. Nobler (Aerotiger 36) that is a candidate for trials later.

Allow me to say that I set up my models with a more sensitive control feel than most, also at this time any change in feel is subtle. There is no “clank” I notice

I really do commend Larry for his fine and creative engineering on both the handle I have and the low overhang version posted.

Jim Hoffman

Howard Rush · « **Reply #22 on:** May 03, 2016, 12:03:15 AM »

Has anybody calculated the kinematics of a control handle? I think it might give some insight into what "overhang" does. One could then go on to see what Larry's handle does.

Larry Renger · « **Reply #23 on:** May 03, 2016, 07:44:36 PM »

Ooooh, a big word!

What exactly do you have in mind to calculate? The rate of line width vs deflection compared to a regular handle would not be that hard, or do you have in mind the relative torque required for a given line spacing?

Either one could be done.

But frankly, Scarlett, I don't give a

So if you want to know, go for it and tell the rest of us. I know you can do it!

Howard Rush · « **Reply #24 on:** May 03, 2016, 09:06:42 PM »

What? You go to all the bother of having a handle 3D printed and you don't know what it does?

Steve Helmick · « **Reply #25 on:** May 03, 2016, 11:02:09 PM »

I saw Howard's 3D printed "Hot Rock-ish" at last NW Skyraider's meeting. We all knew what it did...it did weigh a lot. Light handles count, which I'm afraid may also be a problem with Larry's new handle design. I don't mind my 60 gram TED handles, but might not like heavier than that.

Steve

Jim Hoffman · « **Reply #26 on:** May 04, 2016, 09:42:02 AM »

I flew the Expo Handle on the Ringmaster yesterday. Any difference in feel between it and a traditional handle is subtle and may or may not be noticeable to the pilot. The Ringmaster flew well and was very comfortable in the round and square maneuvers.

I tried watching the handle actuate during maneuvers. I do not recommend that anybody try this. I had my pal join me in the circle and observe the links move. They definitely moved as designed in both the round and square maneuvers. I was not sure my handle motion was enough to actuate during the round maneuvers, but observation showed that they certainly do move in the rounds.

Sorry I cannot say WOW, WHAT A DIFFERENCE, but it was positive and I will continue testing on other planes as time permits.

FWIW both handles in the photo weight 1.8 oz (51 Grams)

Jim Hoffman

Larry Renger · « **Reply #27 on:** May 04, 2016, 03:32:38 PM »

There are major lightening holes inside the handle and it is hollow in front of the grip.

Howard Rush · « **Reply #28 on:** May 05, 2016, 08:27:16 PM »

I took the CAD drawing and got the following:
for δhandle < -30.71 degrees, a_up = 2.48", c_up = 1.23", a_down = 1.63", c_down = 1.43"
for -30.71 degrees < δhandle < -4.79 degrees , a_up = 1.75", c_up = 0, a_down = 1.63", c_down = 1.43"
for |δhandle| < 4.79 degrees, a = 1.75, c = 0
for 4.79 degrees < δhandle < 30.71 degrees , a_up = 1.63", c_up = 1.43", a_down = 1.75", c_down = 0
for 30.71 degrees < δhandle, a_up = 1.63", c_up = 1.43", a_down = 2.48", c_down = 1.23"

See the other handle thread for definitions and pictures. Here's the plot. Did I do that right?

Edit: No, I obviously didn't do it right. I fixed the plot. I should have also noted that the conventional handle to which I'm comparing Larry's has the lines 3.5" apart (a_up = a_down = 1.75")

Curare · « **Reply #29 on:** May 05, 2016, 09:44:16 PM »

Howard, you've shown us a pretty interesting graph for force. How about ciphering what kind of control surface deflection/handle angle we would expect.

For those of us who can't math.

Howard Rush · « **Reply #30 on:** May 06, 2016, 12:00:09 AM »

Quote from: Curare on May 05, 2016, 09:44:16 PM

Howard, you've shown us a pretty interesting graph for force. How about ciphering what kind of control surface deflection/handle angle we would expect.

Good point. That's more pertinent to this exponential handle discussion. I'll see if I can.

Target · « **Reply #31 on:** May 06, 2016, 08:27:14 AM »

Looking at the picture of the two handles, I'd say that the expo handle can be made a bit narrower between the grip and the front pivot area, if someone wanted to make their own, and didn't have fat fingers.

Perry Rose · « **Reply #32 on:** May 07, 2016, 06:54:19 AM »

What design features eliminate binding ,slop and friction at the pivot points?

Larry Renger · « **Reply #33 on:** May 07, 2016, 09:50:55 PM »

It is wonderful to have a fairy (his wife would argue that!) godfather! A wonderful surprise arrived in my mailbox. Howard Rush took my basic 2-D drawings, converted them to 3-D and 3-D printed out my handle design!

I am blown away at the speed that he could do that and that he was interested enough to do it! My undying gratitude to him. It is perfect, and probably better and lighter than the plywood parts I intended to use.

Anyway, the handle was finished within the hour of the main unit arriving, and it weighs under 1.5 ounces. I plan to fly it next week, ASAP! All I had to do is enlarge the holes on one side to fit 4-40 bolts and chamfer the holes for the flat head screws, then tap the other side for the screws. The slow part was adding the safety thong! And he did have a hole for that in the design.

Here it ready to go!

Larry Renger · « **Reply #34 on:** May 07, 2016, 09:57:00 PM »

Quote from: Perry Rose on May 07, 2016, 06:54:19 AM

What design features eliminate binding ,slop and friction at the pivot points?

Those problems just haven't happened. On both the old design and the new one, the links are bushed by brass tubing over the steel bolts. The side loads seem not to be a problem, so I have no reports of binding, and there is no "slop" in the system. Friction has not been reported either, though you could take some measures to eliminate that if you really want to. Grease is good.

john e. holliday · « **Reply #35 on:** May 08, 2016, 03:42:15 PM »

Larry, how much pull will the 3D handle take? Also can he do this within reasonable cost with extra holes for line spacing?

Larry Renger · « **Reply #36 on:** May 08, 2016, 04:15:08 PM »

The handle should take anything you can give it once the links are made of steel. The set in the photos is 3/32' thick Aluminum and I can't visualize them failing either. The old handles used 1/16" Aluminum and none have failed.

Line spacing is achieved by moving the links to the next pivot holes out. This isn't like any other handle where you can just drill more holes.

Larry Renger · « **Reply #37 on:** May 13, 2016, 04:30:04 PM »

I finally got a flight in on the new handle. I flew my Ringmaster with the Ceramic L&J Fox .35. Up till now it seemed heavy and sluggish.

Wow, what a difference the reduced overhang makes!

You guys were right on the button on that being an issue with larger models.

The model's control inputs are now light as a feather, and with the increased exponential of the new design, corners are sharp as can be! It is still smooth at neutral, as I expected.

I'm in love!!!

Steve Helmick · « **Reply #38 on:** May 13, 2016, 04:39:13 PM »

We had a NW Skyraider's meeting only last Tuesday. Howard had nothing for Show & Tell. Maybe he will have one of these at the Judging Clinic tomorrow? He swears that his new "Poland" Impact will be in attendance.

Steve

Larry Renger · « **Reply #39 on:** May 13, 2016, 04:41:53 PM »

I have offered to make him a set of the links, pressure him to accept and make a handle for you guys to play with!

Steve Helmick · « **Reply #40 on:** May 13, 2016, 04:49:14 PM »

Quote from: Larry Renger on May 13, 2016, 04:41:53 PM

I have offered to make him a set of the links, pressure him to accept and make a handle for you guys to play with!

Roger, that! It would be very interesting to have one to pass around and try out. It should be possible to just remove the clips from a TED Handle and plug the lines and clips onto a LARRY Expo Handle, no? Maybe not what one would want to do the weekend before a contest, but otherwise, sure...perhaps use an older model, for sure. Maybe we could get PW to try one out on one of his B-17 stunters?

Steve

Jim Hoffman · « **Reply #41 on:** May 13, 2016, 05:25:43 PM »

This week I had an opportunity to take enough flights on the Expo handle to come to two conclusions for myself:

1) I prefer the Expo on the light weight Ringmaster due to what I perceive as benefits in the vertical eight. To do a rule book vertical 8, keep the shape, intersection AND keep the apex of the top loop over my head, the increased gain during the top loop is beneficial. I will likely keep an Expo handle paired with this airplane.

2) The Expo handle is not an advantage on a ship that is lift challenged. I tried the Expo handle on my OTS Galloping Comedian. This airplane has a very thin wing and can be easily stalled. It flies well but requires significant finesse to fly a quality appearing pattern. I’ve seen this design flown very fast (4.0 second laps) to compensate for the thin wing, I fly at 5.0 sec/lap. I quickly noticed that the Expos handle caused me to over control and stall in a few spots in the OTS pattern. Not a good combination.

Hope this real world testing is helpful.
Jim Hoffman

Larry Renger · « **Reply #42 on:** May 13, 2016, 05:45:22 PM »

"Reality trump theory every time!" Old Confucius saying.

Doug Moon · « **Reply #43 on:** May 13, 2016, 08:44:19 PM »

Quote from: Larry Renger on May 07, 2016, 09:50:55 PM

It is wonderful to have a fairy (his wife would argue that!) godfather! A wonderful surprise arrived in my mailbox. Howard Rush took my basic 2-D drawings, converted them to 3-D and 3-D printed out my handle design!

I am blown away at the speed that he could do that and that he was interested enough to do it! My undying gratitude to him. It is perfect, and probably better and lighter than the plywood parts I intended to use.

Anyway, the handle was finished within the hour of the main unit arriving, and it weighs under 1.5 ounces. I plan to fly it next week, ASAP! All I had to do is enlarge the holes on one side to fit 4-40 bolts and chamfer the holes for the flat head screws, then tap the other side for the screws. The slow part was adding the safety thong! And he did have a hole for that in the design.

Here it ready to go!

Wow that is really cool! Way to go Howard!!

Jason Greer · « **Reply #44 on:** May 13, 2016, 10:15:05 PM »

Howard is awesome. A few months ago I asked him how he liked the Logarithmic flap horn he was using. A few days later, I had a package waiting for me when I got home from work. It contained a few of the critical pieces required to make the horn. I was blown away by his generosity to go out of his way to do that. THANK YOU!! If I'm able to make it to the Nats this year, ice cream is on me at Dairy Queen!

Larry Renger · « **Reply #45 on:** May 14, 2016, 07:27:07 PM »

Quote from: Steve Helmick on May 13, 2016, 04:49:14 PM

Roger, that! It would be very interesting to have one to pass around and try out. It should be possible to just remove the clips from a TED Handle and plug the lines and clips onto a LARRY Expo Handle, no? Maybe not what one would want to do the weekend before a contest, but otherwise, sure...perhaps use an older model, for sure. Maybe we could get PW to try one out on one of his B-17 stunters? Steve

Yes, neutral is neutral

Larry Renger · « **Reply #46 on:** May 16, 2016, 05:57:23 PM »

For me, the minimum spacing of the handle is still a bit wide, so I adjusted the design for 1/2" less minimum spacing. With a laser cutter, Eric should be easily able to make whatever range of spacing's are desireable.

The real hangup is how to get the links produced in an economical manner. Water jet has been suggested, and steel cuts as easily as Aluminum with that process. Anyone with a short run source at liveable prices? Or another inexpensive process? How much might stamping press tooling cost?

How are the Fancher handle metal parts made?

It would be great if this concept could be tried out by a variety of modelers without breaking the bank.

Of course the dedicated experimenter can make the whole thing by hand with a jewelers saw, coping saw and hand drill, but let's get real.

Howard Rush · « **Reply #47 on:** May 16, 2016, 06:04:02 PM »

Quote from: Larry Renger on May 13, 2016, 05:45:22 PM

"Reality trump theory...

You realize that this combination of words will get this thread zillilons of Google hits.

proparc · « **Reply #48 on:** May 16, 2016, 06:24:26 PM »

Quote from: Howard Rush on May 16, 2016, 06:04:02 PM

You realize that this combination of words will get this thread zillilons of Google hits.

Reality Trump Theory Hillary Deadpool.

Mark Knoepfle · « **Reply #49 on:** May 16, 2016, 07:07:06 PM »

Quote from: Larry Renger on May 16, 2016, 05:57:23 PM

It would be great if this concept could be tried out by a variety of modelers without breaking the bank.

Step one would be to get Mr. Rush to share his stl file or files. Printing is cheap depending on where you go. I have kilos of PLA, ABS and nylon waiting to be turned into useful things. I might even be talked into printing a small run. What did you (Mr. Rush) print the handle with? Looks like 50% honeycomb infill, 2-3 layers top and bottom with 3 perimeters as a guess. I can't tell the material without having the part in my hand (and some acetone nearby).

The metal parts can be done pretty cheaply if you buy a hundred sets at a time. I have a friend that sells pancake dies. He has them laser cut and the cutter supplies the steel. I will talk with him this weekend.

Mark