Build : OS .46 FX engine and SPADET LC 40

Started by Mjet, February 28, 2013, 03:27:02 PM

Previous topic - Next topic

0 Members and 1 Guest are viewing this topic.

Mjet

Hello All,
I was never tried for a Nitro Engine and decide to keep distance from nitro / glow engine because of cleaning, oil and other implications, but nitro models always attract me.
I found a old OS .46 FX engine and creates my interest to start scratch building from engine , which needs complete overhauling and adjustments of this engine.
This will also give me a understanding of RC engine and may be helpful to others also.
some pics of engine..

Mjet

I was expecting only Gum deposition and just wants to clean the engine, but both bearing was rusty and completed life.. :banghead: and heavy gum deposition inside of engine ..now i have no choice , i have to overhaul completely.


Mjet

OS used SKF bearings , but I could not found the same in market on time , so  I have changed both the bearings from local market ( Made in JAPAN) at the price of Rs 275. We can change the same bearing in NTN also.

Also changed the glow plug and start the engine , its start , but after heating up, compression was too low and not able to restart again early, so decide to change the sleeve and piston also.

I order the sleeve and piston of ASP S64M from hobby king and replace.
http://www.hobbyking.com/hobbyking/store/__13113__ASP_S46M_Cylinder_Piston_Set.html

Mjet

ASP piston has a small Piston pin hole at one side as compare to other, while the all pistons have same hole size of piston pin on each side.
We have to place a piston pin circlip in small hole and insert piston pin from big hole.

Mjet

Sleeve Pics

sanjayrai55

You should change the entire set: Piston, Ring, Cylinder liner, Crank, Gudgeon Pin, Bearings and remember it is an ABC construction so will be tight initially.

If you use original OS parts, cost is nearly that of a new engine, but it will be as good as a new engine.

sanjayrai55

BTW, if you get original NTN bearings they are good

Mjet

Thanks sanjay ji ,

I could not found the desired NTN Bearings and SKF has not introduced the bearings in after market. My one of friend is working in SKF only , but it will take the time , so just arranged the bearing from local market , will post the pics..

Original OS parts will cost more then a new engine( Piston / Sleeve – 35 Euro + Shipping ). Crankshaft and connecting rod was OK , so used the old.


Mjet

Use full Tips
•   We can remove both bearing easily by heating the crankcase on our house gas stove. Both bearing came out easily with out any hammering.
•   In this engine , two of head bolts lost the grip of of Ellen key , so I used a Drill Bit of same dia of Head Bolt and cut the head of both ( pl see pics).. we     
             can remove any ellen bolts by using this method.
•   Repair the Brocken back plate ( pl see pics)
•   DON'T use any thing except METHANOL to clean the engine, otherwise rubber parts will get swell.
•   Match the notch at sleeve with dowel in head
•   Position the aero mark on piston head towards exhaust

Mjet

#9
Meanwhile, I also started the fuse construction ..here is the progress..
I am targeting maiden flight on Sunday..

Plans are available at Spadtothebone web site.

Used 3 mm coro for entire build.
Made a box of 6 x 2.5 inch from 3 mm ply and used 10 mm ply for firewall.
entire fuse , Rudder and elevator have double layer of coro.
used hot glue to fix rudder on fuse.

sanjayrai55

Spadet's coming along well  :thumbsup: :thumbsup:  Be careful of weight!

I personally don't trust hot glue, but many swear by it

Sorted out the wing issues?

sanjayrai55

Also, fit all control rods while the fuse is open, including throttle. Gets messy later :)

girishsarwal

Great work Mjet, the vert stab looks that of a swanky bizjet ;)
gs

Mjet

Yesterday , Started the wing also , worked till late night  I got the round leading surface in second attempt after  instructions taken from you sanjay ji.
You are correct , the expected AUW may be around 2700 gms.
Thank Girish for encouraging words.

sanjayrai55

Great Mohan. Be careful, your build is becoming too heavy!

Mjet

Sanjay Ji,

I have stopped the further building, because AUW may hit 3 Kg as i again recalculated the weight.

Till date progress - Wing has been Completed with servo and Fuse is almost complete accept forward cowl.

Pl advise , how can i reduce AUW in current Situation.

sanjayrai55

Quote from: Mjet on March 01, 2013, 01:20:24 PM
Meanwhile, I also started the fuse construction ..here is the progress..
I am targeting maiden flight on Sunday..

Plans are available at Spadtothebone web site.

Used 3 mm coro for entire build.
Made a box of 6 x 2.5 inch from 3 mm ply and used 10 mm ply for firewall.
entire fuse , Rudder and elevator have double layer of coro.
used hot glue to fix rudder on fuse.

Mohan:

1. Fuse box: use 3 mm ply. Use minimum, ply is heavy! Only firewall is 6 mm. You need only 3/4 of fuse vertical ply formers
2. No need for doubling Corro
3. Make wing of 2 mm Cooro (but 3 or 4 mm Ailerons)

see my build http://spadworld.net/forum/viewtopic.php?t=14919&highlight=sanjayrai55
4. Buy a 1" hole saw and do "swiss cheesing" (make lightening holes)

sanjayrai55


Mjet

Wing completed - 3 MM coro
Wood Spur
Span - 64"
Chord - 10"
Used Fevibond only
Servo - Hitec HS-311
Total weight along with Servo - 825 Gm

Need suggestions – to reduce the weight , can I cut the white color portion at lower wing and upper wing.

sanjayrai55


sanjayrai55

Mohan, don't cut holes in the wing. I really don't understand why the wing is so heavy, can only be the wooden spars, for which ideally we should use light wood. I normally cut lightening holes in the spars.

But this weight is still OK if you can get the finished model < 2.5 Kg, a good weight

Mjet

May be 3 mm coro ,wood spur - 60' ( 5 mm thick)  , 6 nos  1.5 " screws are responsible for heavy weight.. ( 2 mm coro is not available )

can we cut the holes/ strips  in wing and cover it by tape ( as in balsa models)?

sanjayrai55

It will make it structurally weak. Reduce all that ply in your fuse

Mjet

Sorry for a long gap. here is the pics of complete Fuse.

Mjet

Complete SPAD , ready for maiden flight.