Hello I built guillows piper cub. it took of from the ground about 2 feet and landed suddenly. broke th left landing gear. repaired it and tried to fly again the results were same. here are the spec
odin 1818 220grm thrust
20 amp esc
2 cell 500 mah lipo
4.3grams servo
avionic rcb7x tx and rx
please help!

What KV is your motor? If it is high, give right thrust by putting washers between the motor mount and firewall

It is really difficult to convert the smaller Guillows to RC. 34" span or higher is better

Hello sanjay sir I am using odin 1818 motor from rcbazaar. Com.it is 3000 kv  motor and tried to fly with 5×3 orange prop, 5×5apc, 6×3 orange prop. And also using a 3mm prop Saver.i used a pcb as motor mount.the final weight is around 190grams including battery.the motor gives 220grm thrust at 5 inch prop.

what is the total weight of the model ? where have you got the cg ?

cg should be about 30% of the wing chord and total weight should be max 100 gms
if more then no point trying to fly it. Build a bigger model.


--- oops !  notice that you have posted weight at 190 gms ... this is far too heavy

@kiran rc
You may have seen the rcgroups.com thread on 'Guillow's Piper Super Cub 95 - Brushless conversion'.
Five years old but still interesting.

@saikat I got cg,33% from leading edge. I think the model is a bit heavy but I think with 6 inch prop the motor should give around 250grams thrust.

@k k lyer
Yes I reffered the page of rc group 'gillows to rc convertion' even before I brought this kit.

@kiran rc
You may like to see the estimates by webocalc 1.7.6
I think it underestimates battery size, actual requirement may be 2 or 3 times as much.
33% CG is too far back for test flight. Try 25%.
Incidentally i dont think you need more power. That will only make it harder to fly, and make the wings fold. Perhaps 100-150 gms thrust can fly it gently (say 25-30watts)
My 24 inch span bipe (288 sqin, 280gm) flies easily on 3amps of 2s lipo, or under 25 watts. 10 minutes duration using 50% of 1330mah capacity.
Best of luck.

Hello k k lyer.thanks very much for the information .can u please recommend me the electronics needed for this model.

Hey Kiran have a look here if you haven't already:
http://www.rcgroups.com/forums/showthread.php?t=828198

If I were you then this is electronics I would use:
1) motor:
http://www.rcbharat.com/brushless-motors/184-mystery-a1504-18-2900kv-.html

2) ESC:
http://aeroworks.co.in/store/index.php?id_product=335&controller=product

3) 6 ch Flysky rx

4) Lipo:
http://www.muav.in/?wpsc-product=battery-lipo-gens-ace-2s-rechargeable-7-4v-25-c-450-mah

5) HXT500 Servos(5gm)

6) 5043 props

But seeing that you already have a good small battery, servos , props and an rx, you should change the motor and ESC that I have stated. If you are ok to buy from HobbyKing then electronics from there would be better. As they have lighter motors, ESC and servos.

Thank u rc neil21.ill try to get these.

@kiran rc
Your electronics seem ok. Except that you can save weight by changing the 20a Esc to a 6-10a one. Only problem is that i have not been able to get a 6a Esc for the last 3 months.

The real issue is different.

1. Do you already have experience of flying RC models? If not, this is not a good setup to start with.

2. What is the wing chord / wing area / wing loading? I presume 24x4=96 or 24x5=120. I.e, 0.7 to 0.8 sqft area. Such a small model needs to be under 6oz/sqft or say 175gms/sqft loading. So the all up weight should be in the 120-150gm range. You can't reduce the size of the battery as a 250-350 mah will not cope. Your servos and Rx are already small. Basically you need a larger model to be safe.

Recommendation: Unless you are fairly experienced, remove the electronics, save the Piper and all the effort that went into it, and get/build a 40" span trainer that can use your existing electronics.

Hi Kiran,

Was that a yellow Piper Cub crashed yesterday at Hoskote field?

Just saw a case when I was there yesterday. I saw it take off and it crashed, the motor mount and fuselage  was damaged.
I must agree by Mr K K Iyer that try a bigger trainer if it is has to be a Balsa/Composite one, else   foamies are friends.

 

Tauqeer

@k k lyer
I was thinking of the same to build a larger model but the problem is I dont have enough space to fly and I am beginner.i should go to hoskote to fly bigger models .I flew pzl wilga 2000 successfully.so I have some experience with trainer models.

@tahmadblr
no not my piper cub. I havent visted hoskote since weeks.