Joe K

My Feedback: (1)

I don't know if this will save $ yet or cost me more, so I decided to start a new thread.
Experimental

I have been looking at the head design on the LMH and other than getting a more solid boom strike I don't see why I need for the blades to hing down. Maybe the design makes sure we only BUY LMH blades from LMH.
Good or bad I put a screw in the blade so it can pop up but will not pop down. Will keep you posted. only the next crash will tell.

Spiro

I would certainly say I also “am not an expert. I can not walk on water.” but if I had to venture a pretty good guess I would say they can hinge both ways to save the head from crash damage, even at the expense of the boom. I try some crazy stuff from time to time with my LMH and have had plenty of run ins with the ground where the blades released down, often while inverted or sideways or at some incredible angle of attack or flying between tree branches, or some combination there of. I have gone through 2 tail booms since I got the cursed time drain machine back in 1996, but zero head parts if that is worth anything.

In any event I am eager to find out how your anti boom strike idea works out. Keep us posted.

darthdrk

Im waiting too Joe. Hey Joe by the way, Im gonna try the idea about the exhaust diverter in the other thread you spoke about. Im almost ready to do the JB Weld thing and Im gonna use some Fiberglass cloth. Oh yes and on the boom strike thing, I think my new crutch design has almost solved the majority of boom strikes. I did a couple of hard bounces between today and yesterday to see what would happen. with the stock crutch, I more than likely would have had a funny looking boom by now. Im sure if i smacked the ground really really hard, I might be able to produce a boom strike. I didnt want to go that far. Check out the pic. All I have to do with the exhaust is jb weld it. First I want to clean it up real good and get all the oil residue off. That is just on there by friction. I think This is a good Idea, At least a worth a try for me.

Joe K

My Feedback: (1)

Hey that looks sharp!
Yes the first try on the .074 did not hold I think I did not get it clean enough. Learning from that the .06 has held great so far.

darthdrk

Hey, I started a Web page I just have the homepage mostly completed. It has a generic photo page which i will probably be working on soon. If you click on the photo page theres no lmh stuff there yet. you can check what i do have at http://darthdrk.4t.com/ but there isnt much there yet.

darthdrk

Heres my gearbox modification. This will allow me to make my tail fins removable and changable. Its overlayed with fiberglass cloth and resin. It will definitly out last the stock gearbox 50 to 1. I roughed the outter surface of the gearbox up with a dremel before applying resin and fiberglass.

flyinrog

My Feedback: (1)

Hey Darth, what kind of pipe is that you are using for your diverter? just some scrap aluminum?, have you tried it yet?
Rog

Spiro

Hey Darth,

I just got a new gear box and some fiberglass cloth, resin, and hardener from the hobby store. I would like to make a gearbox like you have, so I can bolt on different tail fins. I have never used fiberglass before… I was wondering if you could answer a few questions and give me a short step to step on how you did your gearbox.

1) Do I glue the small plywood piece onto the gearbox before fiber glassing? What kind of glue? Do you keep the small tailfin yaw angle molded into the gearbox, or sand that flat?

2) How did you keep all of the openings in the gearbox clear from the fiberglass?

3) How many layers of cloth did you use and in what orientations?

4) Do I apply the resin to the geabox first and then press the cloth into it?

5) How much resin should I be using / what should it look like when I am doing it?

6) How long does this stuff take to cure?

Sorry for the barrage of first timer questions, the instructions on the resin, hardner, and glass packages offer very little advice. The do recommend mixing the resin and hardner in a paper cup and not wax or plastic. They also recommend not using the resin over any CA glue. They never really say how to apply the resin or the cloth or in what order…

Thanks in advance,
Spiro

ps: if it motivates you, this is the last thing I need before I can toss the littlebird in the air and get some pics

darthdrk

Heres what I did:
1.) Dont change anything on the angle of the fin mount on the gearbox. Just make sure the seam down the middle is smooth with the rest of the flat surface.
2.) make you a plate from 1/16 plywood. Make sure that its big enough so you can drill the tailfin mounting bolt holes in it(after its completed) without it interfering with the bolt that secures the gearbox to the shaft and make sure when you put the nuts on that they will clear the gearbox and the head of the tailrotor gearbox bolt.
3.)glue on your your ply tailfin mounting plate with CA glue
4.) take a dremel(or sandpaper by hand) and rough up the plastic gearbox casing .
Get an old tailboom or use the good one rub some candle wax on the end to keep the fiberglass resin from sticking You might want to rub a little wax in the other end where the bearing goes. Slide your gearbox on the boom you can hold the boom while working with on the gearbox.
5.)Cut your fiberglass in small pieces about 1/2" squares and some 1"x 1/2" youre going to layering and overlapping these pieces over your gearbox. (cut enough to do about two or three layers over your gearbox)
6.)Brush resin over your gearbox and plate.
Start layering the cloth over the gearbox(Its a messy job) dab the cloth down in the corners and around the edges with a stiff small bristle brush. keep working it until you cant anymore. Mix up a little more resin and repeat. After you get all your fiberglassing done and its cured, start shaping by sanding. Dont forget to remove the tailboom so you can shape that end also. Put boom back in Gearbox when applying more coats of resin. After getting close to to the final shape, mix some more resin and brush it over the gearbox (dont put anymore cloth on). let it set up and cure.
Sand some more until you are satisfied with how it looks. all thats left is drill out your tailfin mounting bolt holes and carefully redrill the hole that your T/R pitch change bellcrank bolt goes in. and open up the recessed nut socket on bottom of G/B (use a razor knife) and open bolt hole on top of G/B. If you get resin on the inside of gearbox where your gearbox bearings goes, it should chip out pretty easy. Do what you can to not let the resin build up in those places.
The last thing you should do before painting is drill your holes for the bolts that you will be using to secure your tailfins. Make sure your bolts and nuts wont interfere with the gearbox and bolt head

The process actually sounds harder than what it really is. It took me less that two hours to complete and thats including the waiting for the resin to harden.

Spiro

Darth,

Thanks much. I will let you know how it goes.

Spiro

Spiro

Darth,

Worked great. I think I will have to use a higher hardener to resin ratio, this stuff is taking forever to cure. Two general fiberglass questions:

1) How do you easily and accurately mix small batches of resin and hardener?

2) How do I get this stuff off of my fingers!?

Spiro

ImRich

My Feedback: (1)

Epoxy is bad stuff, don't get too much on you!

To mix, I lay out two 'lines' of epoxy, equal lengths.. One line is the resin, the other is the hardener. This is the easiest way to be sure you have the same amounts. Be sure to have the lines be the same thickness too. If you pour one slow and one fast you can get different amounts even though the 'line' is the same length. Just watch your pouring speed.

To get it off your hands, use some Alcohol. Rub it on your hands and then wipe off (no, I didn't mean to drink it)!

Try to keep it off your hands. If you can't get some rubber gloves. Some people develop alergic rections to epoxy over time. I've heard it can be nasty. Luckily I haven't (yet)!

Rich

darthdrk

I always add more hardener to the resin to make sure I add enough. Sometimes it sets up to fast on me. To get that stuff off your fingers: well, I use lacquer thinner or M.E.K.
On some brands of fiberglassing resin it takes longer to cure. I find out whats the quickest and use that. I got some resin and hardener from home depot and the auto parts store. Sometimes you gotta watch the stuff they sell, sometimes aint no telling how long its been on the shelf. That stuff does has a shelf life before it starts breaking down. The stuff I use (they are all basically the same) its 14 drops of hardner per ounce of resin. I usually do about 20 drops of hardner per ounce of resin.

Spiro

Darth,

Yeah, that is the resin I was using, or at least the same hardener drop ratio. The second layer I did with more hardener and it set up in a much more reasonable amount of time. As long as there is no harm, I will use a bit more hardener for the final coat to get things moving more quickly.

On another note I am trying to make some sort of exhaust tube similar to those discussed here. I have had no luck attaching the Al tube to the muffler. Has anybody done this and had it last for a while? I was trying silver solder, “solders any metal!”, and that didn’t work at all.

Spiro

darthdrk

The Aluminum exhaust diverter is a good Idea, If you can get it to stay on. I took mine off because it became loose and I started thinking : what if it came off while in flight or even just running on the ground. Im sure it would tear up my main spur gear. If there was a way to probably spot weld it , it would be a novel idea. I just didnt and dont want to take the chance of it comming off while it was running. I may later revisit this idea if I can come up with something that will be a sure hold.
Oh yes, on speeding things up on the curing of the fiberglass: use a heat gun or hair dryer. If you use a heat gun, dont burn it. Heat it a little and let it cool. do it a few times and it should speed things up.

Joe K

My Feedback: (1)

JB Weld cracks had two fall off.
I am now using plumers epoxy putty.
So far so good.

darthdrk

Joek, can you show us a pic?

Spiro

I have fiberglassed a little diverter tube in place. The fiberglass seems to be holding, however the diverter does not keep the body entirely clean. The oil dripping out of the crank bearing still goops everything up pretty well. At this point I am not sure if it is worth it since I still have to clean everything and the cleaning doesn't take any less time.

For what it is worth,

Spiro

darthdrk

Litemachines will also tell you that it is not good to run the clutch dry. I was told that it is a good thing that your clutch get that goop stuff all over it. Seems like the greasy stuff leaks from everywhere on the engine, even out of the carb.

Spiro

After several flights with different bodies, it is my opinion that the exhaust diverter tube is not worth the effort. The amount of goop naturally dripping out of the engine (from seemingly every crack and orifice) still gets slung all over the place and just as much cleaning is required. That being said, I would also not view a reverse crutch to be worth the effort for the same reasons.

For what it is worth,
Spiro

Spiro

Darth,

I noticed in one of your older threads you mention some custom landing gear you have made:

http://www.rcuniverse.com/showthread...der+and+longer

"I made my landing gear out of 1/4"dowel, 5/16" aluminum tubing and 3/32nd music wire. Ive made it about and inch taller and wider."

I was wondering if you could give a little step by step description of what you did to make the gear. Specifics like how the music wire attaches, ect., would be great. I would like to make another set of gear for my LMH and I was wondering how yours held up to wear and tear.

Thanks in advance,
Spiroo

darthdrk

It didnt hold up like I expected. I went back to the regular gear. I plan on revisiting the landing gear issue soon. What i did was the dowel and aluminum tubing thing also. For the front and rear of the skid I made those sections aluminum The front and rear struts were of a thicker gauge wire which were L-shaped at the bottom like the stock LG. I put slots in the dowel that the L shaped ends would fit in and I slid the aluminum pieces over them. I even slotted the aluminum pieces so that they would slide over the gear and kinda lock in place. I probably should have either epoxied or CA'ed the aluminum pieces over the L-shaped ends. I noticed that the aluminum wore out pretty quick from take off and landings on concrete. There are some things that I realize that I could have done differently and will the next time I revisit this mod which I shall do soon.

Joe K

My Feedback: (1)

The plastic crutch was a complete flop.
It cracked in flight, flexed, broke even more in crash.
Had to much flex. Motor started to melt crutch.
NOT GOOD!

Spiro

" Motor started to melt crutch. "

I love the smell of melting plastic in the morning. It smells like, defeat.

Sorry to poke fun at your woes, but that just made me smile

davensocal

My Feedback: (1)

Umm, not sure if I am straying from the topic, or bringing us back to the topic....

Here are a couple of pics of something I have been working on. It only applies to the to the electrics though.. For some reason, we are driven to make the electrics even quieter..

These shots are from an install I did on a friends heli..