You'll probably get some teasing SeamusG from the fact you evidently exerted heavily weighted force downward on that 46LA.

If everyone promises not to tell anyone, particularly a Fox engine guy, a couple years ago I contemplated all the ramifications and threw a Fox into the trash. I sent it to the landfill. Two thousand years from now some guy will dig it up and try to get it running right. He'll either commit suicide in the process or throw it into the rocket garbage scow headed for the sun. A fitting end lol.

I have an LT-40 that porks out at just over 8 lbs. I had to add weight to the nose too. One of the reasons it's so heavy, I didn't know what I was doing.. It was my first build.

Flies on Electric just fine... It'll still float in on landing for 2/3 the length of the runway....

Now that's a possibility.. 'course i was thinking more along the lines of a 12 oz adult malted beverage....

Things that I learned at my LHS ...

The ARF I saw is powered by a super tiger 46. It's a trainer ofa new club member that needed to repair some crash damage.

The construction of the ARF and kit are like day and night. Kinda like the difference between the Senior kit & ARF.

Wing construction:

the ARF ribs are all lightened with 3 holes each. the kit ribs are solid. the balsa stock used in the ARF is thinner than that used in the kit. the ARF attachment to the fuse is with a bayonet in the front and 1/4-20 nylon bolts in the rear. the kit uses #67 rubber bands. the ARF uses 2 hard ply root ribs in addition to the balsa root rib. the kit uses 2 balsa root ribs. kit weight does not include 12 rubber bands. the ARF aileron torque rod does NOT use a brass tube as a bushing. the kit aileron torque rod uses a brass bushing tube. ARF overall weight is 26 oz. w/ servo & controls. kit overall weight is 35 oz. w/ servo & controls. ARF wing is at least 9 oz lighter than the kit wing.

Fuse construction:

the ARF sides are doubled balsa wood with no lightening holes in the sides or top or bottom of the rear section. the kit is doubled plywood (1 lite 1 std) on the sides with lite ply top and bottom sections w/ total of 12 lightening holes. formers appear to be of similar construction. ARF formers have control rod supports where only 1 kit former has rod supports. ARF & kit firewalls look similar. ARF uses weird hardwood tri-stock for reinforcement.

Tail feathers: differences unknown.

Control rods - both recommend that 9" pieces of 2-56 rod threaded on one end be stuck up both ends of the inner tube. Vasoline anybody?

I compared the weight of the OEM wheels against same size foamies. 1.9 oz for OEM and 1.1 oz for foamies.

I have had 3 LT-40's with anything from a .40-.46, bottom of the food chain engines, worn out, etc. I've added pounds glue, smashed them into pavement, rebuild with Gorilla glue and steel beams. LT-40's will fly regardless of how heavy and how ugly. It's the wing. It's big and lifty and very mauverable. I mostly fly minimal power flight, on the edge of stalling and 3 feet from the ground. That means 1/8 throttle and elevator at a 45 degree angle. They are wonderful, late afternoon, sit back in an easy chair, beer in hand, flying machine. Enjoy the weight. Don't worry, just balance and fly.

Our LT40 (with minor alterations for 2 build mistakes) came in at about 7lbs too. I'll second the great fit of the OS46AX!

The weight and mounting footprint of the OS 46 / 55 AX and the Evolution 52 NX are the same. The Evo has the same bore with a longer stroke as the 46. The 55 AX has a bigger bore yet but shorter stroke than the 52. Bottom line? Does it really matter?

I hope to wrap up the LT-40 assembly and get it out for a trimming flight soon.

RC - I'll bring a brown bag to the club meeting tonight. If you're there I'll let ya take custody of the remains.

If your LT-40 really weighs over 7 pounds, you are going to find out two things really quickly: 1) the front nose gear will bend at the first bad landing. 2) the rear gear will spread out (and stay that way) at the first bad landing. I love the LT-40 powered by an OS FP .40 - had plenty of power for training. Built one years ago, but Sig landing gear is notorious for bending as the metal is soft. If you teach takeoffs last, you could get away with conventional gear and less weight (just a thought).

I kept my comment about the "lady with skinny legs" to myself. There may still be an excuse for converting her to a tail dragger - wait, it's a club trainer. Something to think about for sure.

See you there!! [sm=thumbs_up.gif]

Just a suggestion...I had horrible troubles getting my AW 1.20 Yak 54 to meet "CG" specs. It was god awful tail heavy. Rather than just adding weight for the purpose of making the suggested "CG" position, I also added horsepower to throw the weight around. I put an OS 160 in the plane and the "CG" came out dead on without having to move all kinds of stuff around.

I would go with the Evo 55...BUT before you drill the screw holes, check the "CG" while shifting the engine further forward on the engine mount. When you find the sweet spot, lock her down.

I would never add weight on any aircraft without adding horsepower, too. Just me, though...

I had a NextStar Select that had a .46 engine. That RTF weighed well over 8 lbs, yet it flew just fine, for what its worth... All main landing gears deflect on hard landings. This action saves the fuselage from major damage while learning. At least twice, I punched a hole in the bottom of the fuselage from the main landing gear deflecting up into the fuselage. Yes, it was a real noobie landing BUT that is why you fly a trainer.

Another great trainer is the 3D Hobby Shops EBT. It is extremely light and flies like a dream. It would be a snap to learn with this trainer. Make sure to tone it down using low rates and expo for first time pilots, though. It has a very big elevator for a trainer. I actually fly it on high rates and do snap rolls and 5-foot diameter loops...yes, 5-foot...as many in a row as the battery will allow. It flies superb!

I learned on a lt40 that was a kit i bought cheap with tower 46.Second flight motor was heating up and seized.That afternoon went to Lhs and bought a os 46 ax been great since that plane very heavy around 7lbs and with 6 0z in the nose.
I was later given a lt 40 arf that was assembled but not flown.I was almost ready for 2nd plane so i cut 6 in out of wing took out all diheidale(bad spelling)put a 55ax on it,plane all was cg-ed and battery and receiver was mounted just behind the servo tray.come out about 1lb lighter.Flys like a different plane hovers at 1/2 throttle knife edges like a stick great fliying plane now.

bigaco

Just a thought, if you're still looking to reduce a few ounces here and there. Wing saddles can be modified, and the wing could be moved back. Half of an inch is a HUGE shift in CG weight.

That being said, as so many of the other guys have pointed out, it's going to fly just fine if you do nothing at all..

Also, I have not read this thread thoroughly post-by-post but I didn't see anything about verifying the CG location under the wing. I'm sure you did, but I thought I'd mention it in case.

Looking forward to seeing how it flies.

Jim

I took the plane to our monthly club meeting. Primary goal was to demonstrate to our finance officer that the LT-40 was real and to get reimbursed for the cost of the plane. Secondary goal was to get input from the members. Btw, our club (I believe this to be true) is currently the largest active-member club in the AMA. Quite a diverse group - looking for their input.

A simple suggestion (and I think that RCPilot may have suggested it as well) was to cut "lightening holes" in the elevator and rudder surfaces. Any weight saved would be tripled at the firewall - 2 oz out back = 6 oz at firewall. Don't know how easy it is to "loosen" Ultracote bonded to Ultracote. Will try a test strip. If it is pretty simple, this would be fairly easy to do. If I do, I'll post the results. My goal would be to be able to move the engine back 1/2" and lose the Higley heavy spinner (2 oz.). As I become more comfortable with the plane I'll move the CG back. Options will include replacing the heavy spinner with the plastic Dubro unit and moving the battery back. These both can easily be reversed for training night.

A skinny legs comment was made. Suggestion was to consider using the traditional main gear style (flat aluminum sheet rather than the 5/32" wire ) used with tail draggers. I'm embarrassed that I didn't consider this a while back 'cause I've got several sizes on my work bench. Since I do not intend on having a student land this airplane - it's all up to me. Our club training guidelines allow the use of club trainers until the student is ready to take off and land. Then the need their own plane.

Another gear strengthening approach came to mind - but this one will be at the cost additional weight. Create a "V" out of 1/8"wire. The width at the points would be the same as the distance between the static landing gear "bends"that create the wheel axles. The point of the "V" would be perhaps 2/3 of the distance to the bottom of the fuse. Attach the "V" tips to the landing gear wire by wrapping thin wire around both peices then "tinning"the wire wrap with solder. The "V" would act as a doubler - still providing spring action but much stiffer. We'll see how the OEMLGwire works out first.

Hope to maiden tomorrow.

TTFN,

Btw, waiting for RCPilot to chime in - he's considering putting a 4Star60 wing on a modified LT-40 wing saddle - moving the LEof the wing back 1/2" or so. Hey, why not? No dihedral to speak of. Separate aileron servos. Asymetrical profile. Airfoil overall length within a couple of inches of the LT's. All-up weight ready-to-fly is 2 lb 3.6 oz for the 4Star as compared to 2 lb 2.7 oz for the LTwing (yes, I have a 4Star60 wing standing next to my LT-40 wing). The chord of the 4Star is 12.9"and the LTis 13.5". Just have to add a "twin dowel" mounting point at the front and 1/4-20 blind nuts at the rear.

TSP- yea, got the CGpoints laid out. ROT - center of main spar is the "gentle"CGlocation of 3 1/2".

That LT-40 and 4*60 bash has been in my head for a few years.

By moving the LE of the wing back, it changes the balance point on the plane, so there would be less rick of a tail heavy plane. Not to mention the use of a heavier motor up front. Don't forget that moving the wing back also allows for servos in the tail.

I'd move the vertical stab back so the hinge line was even with the hinge line of the horizontal stab. Split the elevators, pinch the fuse tight at the tail. Run the rudder all the way to the bottom of the fuse and lengthen the cord about 2"

Set the stab at 0 and set the wing at 0 or maybe negative about 1/2 degree at the LE.

I think it would be a kick with a .60-1.20 size motor.

Thanks for the parts engine SeamusG. [sm=thumbup.gif] What did you win at the meeting?

Btw, our club (I believe this to be true) is currently the largest active-member club in the AMA. SeamusG




Huh? You don't even appear to be the largest AMA club in Colorado, ARVADA ASSOCIATED MODELERS members 198 , JEFCO AEROMODLERS CLUB members 206 , much less in all of AMA, SANTA CLARA CNTY MODEL AIRCFT SCCMAS members 243 , BAYSIDE RC CLUB INC members 247. I have no idea who is the biggest AMA chartered club but just a quick check shows your mistaken. Probably the thin air, I used to live in JEFCO myself .........

Ahhh, forget him. Guys from Oregon are just grumpy.

I thought about checking out the stats on that and then decided I had better things to do. This means that Grumpy didn't have anything better to do.

I used to know where the biggest club was. Proud to say I've clean forgotten that now.

By the way, you're right, it was suggested very early on (I think it was RC too) that you should cut lightening holes in your tailpieces. It's a commonly used and usually very effective method. Remember to stagger your holes so that you don't have a straight line of lots of holes close together making a very weak spot waiting to snap off. Use a small hole saw, like 1" or so. Start cutting in from one side (top) and then come back from the other (bottom) to make the cut clean. Remember to use HEAT to help you to peel off the coating. A heat gun or your covering iron will work. Don't force it, it will come off when the heat is right. Slow and steady gets it done.

By the way, That is a REALLY pretty job on that plane, I'd be proud to own it. Kudos.

Jim


Jim

The holes belong to LW. An all I have been trying to do is loose weight
Larry K

Geez - I thought I said "the largest active-member AMA club in our zip code" ...

Hey Chris - thkx for picking up "the card" - it's a gift card - it has no denomination. Guess I gotta go down to Action Hobbies and find out. Thinking of covering the Hog Bipe with Coverite or SolarTex.

Ya know those darn 'spensive battery chargers don't work if ya leave the plane's switch in the "on" position.

Sorry LW - I knew Iheard it somewhere -

Using that fabric covering is one way to turn a good model into a heavy model. I've used all of the iron-on fabrics and have come to the conclusion that if I absolutely must have fabric on the model, I'll stick with the old silk and dope techniques of yesteryear. It is lighter, easier to repair and is easier to refinish when needed. Just my two cents.


Ed Cregger

Ed - good to know. I'm not going to jump into the pool of fabric covering w/o doing a bunch of research.

I don't know where you got the number of only 178 members, but thats less than 1/2 our membership. [sm=spinnyeyes.gif]

Read the first paragraph on the home page:
http://www.arvadamodelers.com/

I think our last count was 374 members. I don't know if thats the largest, but it's enough paying members to keep my club dues at only $35 per year. [sm=lol.gif]

On the subject of fabric covering:
One of our members brought an old timer airplane to the meeting last night. It was covered in solartex. It didn't feel heavy to me. It was powered with an axi 28-20 motor, a 40amp ESC and a 2200 li-po. Span was about 70". Total weight on the model was UNDER 5lbs.

I've been wanting to cover in fabirc too. I bought the stuff to cover with Sigs Koverall. I have a 40% Emeraude kit that needs cloth covering. But I need a "practice" model first.