RE: cv 12 mounted on lmh 117  
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RE: cv 12 mounted on lmh 117 - 12/6/2003 12:36:15 AM   
Spiro



Posts: 312
Joined: 4/14/2003
From: Mesa, AZ, USA
Status: offline 		I would agree that this is not a project to be taken lightly. A thrown blade could easily seriously injure or kill someone, if struck in the wrong spot. The suggested 2500 rpm produces nearly 30% higher centrifugal blade forces over 2200 rpm. I do not know what the factor of safety is on these parts, nor what condition any one persons equipment might be in, but I wouldn't want to be anywhere near a helicopter that far past its never exceed rotor speed. If the rotor shed a blade at some 2500 rpm that thing would be coming at you at nearly 100 feet/sec. How would you like to take that to the throat tip first?

Also, for reference, my Vmax7 hits 2200rpm at the head all day long with 6 degree grips (24860 engine RPM, at 11.3:1 gear ratio). When I first ran the motor and tached the head speed, I called up Paul at LMH to ask if this was ok, since the original documentation stated never exceed of 2000rpm. Paul also told me that 2200 would be all right, but not to go any higher. I usually tach my LMH before I put it up and set the needle to keep the head speed below 2200. It flys with plenty of authority with around 2100rpm head speed.

My recommendation for using an alternative engine would be to set the max throttle position such that max head speed is where you want it, as notasme suggested. This would allow you to set the needle as needed so the engine runs correctly, but still would guarantee you don’t accidentally over speed the head.

For what it is worth, and play safe!

Spiro

(in reply to notasme)
       Post #: 51

RE: cv 12 mounted on lmh 117 - 12/6/2003 1:03:58 AM   
darthdrk



Posts: 1074
Joined: 12/7/2002
From: Munford, TN, USA
Status: offline 		Can I chime in?
Just a thought, with a metal feathering plate or CF plate which are available as aftermarket parts Also there is a distributor over in Germany selling Carbon fiber blades. Would these upgrades make that engine set up a little safer at the higher RPM head speed. It will take alot of force to rip through the fibers to sling(throw) a blade. Also i was thinking with the Longer blades and boom it should help in maintaining a lower RPM. Also A little more weight could be added to the chopper. I notice a big difference between the Electric and the gas versions weight and I also notice that the electric has and develops a higher head speed. I have both chassis and My electric version with the same blades and boom as the gas version takes off like a rocket and its a much heavier setup. help me out here.

_____________________________

Owner/OEO/Mastercraftsman of Darth's
Helibodies Darthdrk@juno.com

(in reply to Spiro)
       Post #: 52

RE: cv 12 mounted on lmh 117 - 12/6/2003 1:50:06 AM   
lyk2fly


 

Posts: 357
Joined: 7/1/2003
From: Turtletown, TN, USA
Status: offline 		I don't know what the saftey factor is for the LMH but if the manual says 2000 is the safe "never exceed" head speed, and the LMH folks provide an engine upgrade (vmax7) that is going to exceed that speed....and then tell you that it is alright......that suggests to me that they may not know what the safety factor is either. Notasme has done a wonderful thing with his engine modification. He has plowed new ground.....and that does involve risks. Maybe now the LMH folks will learn how desperate their customers are to find a dependable engine. I can't understand how a company that seems to be as popular as they are has not contacted another engine manufacturer to build an engine to their specs. The vmax6 is pathetic and I'm afraid most people feel the same way about the vmax7. I'm also afraid that instead of correcting the nitro problem the LMH folks may shift their efforts to electric. Most upgrades seem to be for the 120. I have nothing against electric....but I prefer nitro. The 110/116/117 helis provide many hours of enjoyment and I have learned much about flying with my 110. But I've also had hours if disappointment.
Mark

(in reply to darthdrk)
       Post #: 53

RE: cv 12 mounted on lmh 117 - 12/6/2003 2:52:42 AM   
spdfrek


 

Posts: 114
Joined: 8/28/2003
From: Grassy Butte , ND, USA
Status: offline 		Oh I'm a relatively safe guy....But I wanted to see what everyone elses thoughts were on this safty factor here.I mean...you should never need to exceed 2200 rpm with 6/6 grips on there.Should MORE then fly well enough at that point...especially seeing as the engine has the power to pull those grips.However simply limiting throttle movment cant gaurantee that it'll never over rev...perhaps if it runs lean cause a fuel filter clogs or the like...I suppose one good afix a tach that could be remotely monitored and throttle up slow and steady...See what rpm in blew up at.....but thats not something I really wanna try badly...I agree....No one should attempt this unless they know what they are getting into...I for one am ok with the problems...And I am just looking for a reliable engine over here..I'll be sure to keep everyone posted....BTW is there any harm in flying with snow as long as electronics are taken care of?Just curious....Fixed wing guys do alot so....Thanx again for all the help you guys provide.

Joey

(in reply to lyk2fly)
       Post #: 54

RE: cv 12 mounted on lmh 117 - 12/6/2003 3:04:29 AM   
darthdrk



Posts: 1074
Joined: 12/7/2002
From: Munford, TN, USA
Status: offline 		Seemingly there was a time and sometimes still, getting a good V7 upgrade engine was a roll of the dice. I had have 3-4 V6 engines and overall I rate the engine at a D+ One engine Ive burned more gas trying to get it to fly than actually flying. I went through three V7 engines until I finally got a winner, my fourth engine. Its been a real charm. I rate this engine at an A. but the fustrations that came along with weeding through V7 engines was a Pepto Bismol experience. When I had time and wanted to fly, I couldnt. Now I would like to fly but do have no time (working on Heli bodies). I personally do feel as if LiteMachines is turning their back on the nitro guys. Also dont think that the electric guys dont have their share of problems because they do and i think even more so. It really dont take as long as it has to address the sorry engine problems with the nitro helis. Seemingly its the only problem that we who fly these things are having (myself, use to have engine trouble because I got a good V7 engine over two gallons of gas through it in less than a year). looking at the forums, It seems electrics are out selling gas helis. But the cost of operating them is much more expensive. Well, with Lipo batteries comming out 20-30 minute flights are possible from what ive read but realisticly who can find flying that long fun(I understand you can land whenever also). Its good to be able to come in and land every now and then to give the heli a once over. I guess its still going to be a to each his own when it comes to gas or electric. Now does it really take that long for Litemachines to remedy the nitro problem???. Mabey someone will come up with a great resolution and choppahedzs will get wind of it and try to capitalize on it... mabey. We'll see.

_____________________________

Owner/OEO/Mastercraftsman of Darth's
Helibodies Darthdrk@juno.com

(in reply to lyk2fly)
       Post #: 55

RE: cv 12 mounted on lmh 117 - 12/6/2003 3:07:22 AM   
lyk2fly


 

Posts: 357
Joined: 7/1/2003
From: Turtletown, TN, USA
Status: offline 		Joey, I don't think the snow will hurt your heli. The cold will make the plastic more brittle, so it will break much easier should an impact occur.
Mark

(in reply to spdfrek)
       Post #: 56

RE: cv 12 mounted on lmh 117 - 12/6/2003 4:49:03 AM   
spdfrek


 

Posts: 114
Joined: 8/28/2003
From: Grassy Butte , ND, USA
Status: offline 		Aim for a big snowbank then....got it This should be a good learning experiance for me at any rate.

Joey

(in reply to lyk2fly)
       Post #: 57

RE: cv 12 mounted on lmh 117 - 12/20/2003 11:09:01 AM   
iloweru


 

Posts: 24
Joined: 12/20/2003
From: duarte, CA, USA
Status: offline 		i also have installed a better motor then the stock one. i tried v6 and v7 with no luck at learning how to fly helis.then i put a xtm 15ps in my 110 the power it has is unreal. i just started flying heli i am able to fly as hi as i want with the upgrade. if any of you heli fliers are thinking of doing this to your heli DO IT you won't be sorry . except that you didn't do it sooner.

(in reply to notasme)
       Post #: 58

RE: cv 12 mounted on lmh 117 - 12/20/2003 5:51:24 PM   
T.W.


 

Posts: 947
Joined: 10/25/2002
From: Way Up North , UNITED KINGDOM
Status: offline 		Hi iloweru, maybe you'd like to post an article telling (and preferably showing) how you fixed your motor in place, and how you got-over any problems you encountered along the way too. I'm not alone in looking for an easy (non-engineering) way to do what you've done

As Darth said, the stock engine is the only problem that we who fly these things are having to contend with, so any additional information you have would be of great interest to me, and to many others too

Tony

(in reply to iloweru)
       Post #: 59

RE: cv 12 mounted on lmh 117 - 12/22/2003 10:21:52 PM   
iloweru


 

Posts: 24
Joined: 12/20/2003
From: duarte, CA, USA
Status: offline 		it has a xtm 15 motor with a losi flywheel and clutch , 19 tooth losi bell a longer main shaft to move the gear down to hit the bell gear bigger fuel tank and a 6 cell battery pack. i have pix but i dont know how to post them.

(in reply to T.W.)
       Post #: 60

RE: cv 12 mounted on lmh 117 - 12/22/2003 11:00:56 PM   
iloweru


 

Posts: 24
Joined: 12/20/2003
From: duarte, CA, USA
Status: offline 		here are some pix

Attachments
Click to see fullsize image.
Click for fullsize 		Click to see fullsize image.
Click for fullsize 		Click to see fullsize image.
Click for fullsize

(in reply to iloweru)
       Post #: 61

RE: cv 12 mounted on lmh 117 - 12/23/2003 5:43:09 PM   
T.W.


 

Posts: 947
Joined: 10/25/2002
From: Way Up North , UNITED KINGDOM
Status: offline 		Thanks for posting your pix iloweru

To me it proves the point that "sometimes you just have to try these things." Your LMH must weigh a lot more than was originally intended, but it flies; and the balance point must move dramatically between the take-off and the landing, but it still flies

Well-done! The fact that your set-up works is inspirational. I really must find one of these engines and give it a go myself

Tony

(in reply to iloweru)
       Post #: 62

RE: cv 12 mounted on lmh 117 - 12/24/2003 3:05:04 AM   
iloweru


 

Posts: 24
Joined: 12/20/2003
From: duarte, CA, USA
Status: offline 		it is heaver then stock but the motor makes up for it. it stays level in hover , flys the best it ever has.

(in reply to T.W.)
       Post #: 63

RE: cv 12 mounted on lmh 117 - 2/13/2004 12:17:44 AM   
T.W.


 

Posts: 947
Joined: 10/25/2002
From: Way Up North , UNITED KINGDOM
Status: offline 		Just when my V-7's starting to look like it may work (hopefully) I've found an ad for an OS car engine I could fit to my LMH instead. But I can't find any reference to this particular OS engine on the 'net and I'm starting to wonder if the ad's incorrest. The ad says that the engine is an: "os 11 cx" Is there such a thing? Would it have enough power to do the job? What do you think?

Tony

(in reply to lyk2fly)
       Post #: 64

RE: RE: cv 12 mounted on lmh 117 - 2/13/2004 2:16:46 AM   
fiat


 

Posts: 326
Joined: 9/15/2003
From: albemarle, NC, USA
Status: offline 		Tony it's probably an os.10 or .12 and yes I do beleive that this is plenty of power. If this next v-7 dies I am going to take the motor out of my sons rc car it's an os.12.. I try this combo and see.. Alan

(in reply to T.W.)