RC India
Welcome Guest, please login or register.
 
Pages: [1]   Go Down
0 Members and 1 Guest are viewing this topic. Topic Tools Topic Tools 
Read
« on: December 14, 2016, 10:22:06 AM »
swapnilnimbalkar
Plane Lover
Senior Member
***

Reputation Power: 2 
swapnilnimbalkar has no influence.
Offline Offline

City: Thane
State: Maharashtra
RC Skills: Beginner
Posts: 157
Join Date: Nov, 2016




Hello everyone,

I am trying to build KFM3 airfoil. I made the wing. Recommended thickness of the wing is 9-12% of chord length.

I made a mistake and my wings thickness comes out to be 14%.

The question is: Will it work?

Thanks.

Swapnil
Logged
 

Read
« Reply #1 on: December 14, 2016, 10:27:48 AM »
rastsaurabh
Plane Lover
Forum Hero
*****

Reputation Power: 16 
rastsaurabh has no influence.
Offline Offline

City: Noida
State: Delhi
RC Skills: Beginner
Posts: 1316
Join Date: Mar, 2012



Yes it will work no doubt.

14% will only induce more drag & Lift.
Plan for a little more powerful engine ( motor) than recommended. There may be tweaking required for down thrust.
Logged
 

Read
« Reply #2 on: December 14, 2016, 10:59:49 AM »
swapnilnimbalkar
Plane Lover
Senior Member
***

Reputation Power: 2 
swapnilnimbalkar has no influence.
Offline Offline

City: Thane
State: Maharashtra
RC Skills: Beginner
Posts: 157
Join Date: Nov, 2016



Thank you so much.
Logged
 

Read
« Reply #3 on: December 14, 2016, 08:28:57 PM »
swapnilnimbalkar
Plane Lover
Senior Member
***

Reputation Power: 2 
swapnilnimbalkar has no influence.
Offline Offline

City: Thane
State: Maharashtra
RC Skills: Beginner
Posts: 157
Join Date: Nov, 2016



Yes.
The plane did fly. I am so happy as it was my first build and first flight.
Unfortunately after reaching certain height it plunged to the ground so hard that I'll have to build new one.
Logged
 

Read
« Reply #4 on: December 14, 2016, 11:01:02 PM »
rastsaurabh
Plane Lover
Forum Hero
*****

Reputation Power: 16 
rastsaurabh has no influence.
Offline Offline

City: Noida
State: Delhi
RC Skills: Beginner
Posts: 1316
Join Date: Mar, 2012



"Unfortunately after reaching certain height it plunged to the ground so hard that I'll have to build new one."

This is very normal in this hobby.

A few leave because of this and a few aim to make better next time.
Logged
 

Read
« Reply #5 on: December 15, 2016, 10:01:36 AM »
swapnilnimbalkar
Plane Lover
Senior Member
***

Reputation Power: 2 
swapnilnimbalkar has no influence.
Offline Offline

City: Thane
State: Maharashtra
RC Skills: Beginner
Posts: 157
Join Date: Nov, 2016



Yes. Thanks for moral support.

This time i will go with pusher configuration.
Logged
 

Read
« Reply #6 on: December 15, 2016, 10:20:00 AM »
rastsaurabh
Plane Lover
Forum Hero
*****

Reputation Power: 16 
rastsaurabh has no influence.
Offline Offline

City: Noida
State: Delhi
RC Skills: Beginner
Posts: 1316
Join Date: Mar, 2012



Pusher planes end up tail heavy... Incorporate bigger nose fuse to counter CG.
Logged
 

Read
« Reply #7 on: December 15, 2016, 09:06:42 PM »
swapnilnimbalkar
Plane Lover
Senior Member
***

Reputation Power: 2 
swapnilnimbalkar has no influence.
Offline Offline

City: Thane
State: Maharashtra
RC Skills: Beginner
Posts: 157
Join Date: Nov, 2016



Yes I will. Thanks for the tip. Few more tips are welcome.
Logged
 

Read
« Reply #8 on: January 01, 2017, 06:56:03 PM »
bmblb
Plane Lover
Forum Veteran

****

Reputation Power: 5 
bmblb has no influence.
Offline Offline

City: Bengaluru
State: Karnataka
RC Skills: Intermediate
Posts: 312
Join Date: Apr, 2010



I made a mistake and my wings thickness comes out to be 14%.

The question is: Will it work?

Swapnil

Swapnil......did you try it? any pics?
Logged

"The Flight Of The Bumblebee"
 

Read
« Reply #9 on: January 10, 2017, 11:26:58 PM »
swapnilnimbalkar
Plane Lover
Senior Member
***

Reputation Power: 2 
swapnilnimbalkar has no influence.
Offline Offline

City: Thane
State: Maharashtra
RC Skills: Beginner
Posts: 157
Join Date: Nov, 2016



The plane did not fly. I crashed it even before taking off.

IMG_20170108_134402.jpg
Re: Question: KFM3 Airfoil
* IMG_20170108_134402.jpg (56.48 KB, 800x450 - viewed 154 times.)
Logged
 

Read
« Reply #10 on: January 11, 2017, 04:08:31 PM »
samayaraj
Plane Lover
Active Member
**

Reputation Power: 1 
samayaraj has no influence.
Offline Offline

City: Chennai
State: Tamil Nadu
RC Skills: Beginner
Posts: 64
Join Date: Oct, 2011



Can you tell the weight of model, motor spec, prop.

I have tried the same pusher model in coro sheets. It just hit the ground. I believe the motor angle need to be slightly up. This creates a upward moment I feel. Experts correct me if I am wrong.
Logged
 

Read
« Reply #11 on: January 11, 2017, 06:08:16 PM »
bmblb
Plane Lover
Forum Veteran

****

Reputation Power: 5 
bmblb has no influence.
Offline Offline

City: Bengaluru
State: Karnataka
RC Skills: Intermediate
Posts: 312
Join Date: Apr, 2010



The plane did not fly. I crashed it even before taking off.

swapnil...this can be frustrating...so here are some tips:
1. Do away with the ailerons and landing gear for your first plane - you can hand-launch.
2. Was the prop fixed in the correct direction? ( assuming you used a suitable/adequate motor)
3. How much throws did you set?
4. Did you do a glide test...to ensure the CG was right?
5. Can you simplify your Tail surfaces? Are the horns fixed 'correctly'?

...While it is possible to build and successfully fly your first plane ' all by yourself', there are several things that can't be covered here - do you know any other flyer in your area? This can be invaluable as what you really need is someone who can really be there to see what is happening.....unless you take the pain of shooting/uploading a video of the crash.

OR....start afresh and build a new plane.

If you can share the equipment and material you have access to....we could put together a plane that you can build in a day.

here's something you may like http://www.rcindia.org/electric-planes/pusher-trainer-for-beginners-bgnr/

Dont bother building a wing described in the thread....KFm 2 works just fine.
Logged

"The Flight Of The Bumblebee"
 

Read
« Reply #12 on: January 12, 2017, 11:19:19 AM »
swapnilnimbalkar
Plane Lover
Senior Member
***

Reputation Power: 2 
swapnilnimbalkar has no influence.
Offline Offline

City: Thane
State: Maharashtra
RC Skills: Beginner
Posts: 157
Join Date: Nov, 2016



Thank you so much for the input.

As per my understanding the prop was fixed at suitable position with little bit of downthrust.

I did test glide with it. It did glide well. As far as throws are concerned I did not calculate it. Will do it n tell you.

Yes the horns are fixed correctly.

I will increase the wing span, currently it is 40". So I will add 6" on either side with little bit of dihedral. Total will be 52".

I am afraid of hand launch thats why i did the landing gear and all. Also adding landing gear corrected my CG.
Logged
 

Read
« Reply #13 on: January 12, 2017, 12:35:08 PM »
VTOLkarthik
FIREFLY
Plane Lover
Senior Member
***

Reputation Power: 4 
VTOLkarthik has no influence.
Offline Offline

City: Bangalore
State: Karnataka
RC Skills: Intermediate
Posts: 246
Join Date: Jul, 2012

Thr r mre planes in d sea tan thr r ships in d sky




I am afraid of hand launch thats why i did the landing gear and all. Also adding landing gear corrected my CG.

Even I had the same fear. let go off it. Just have a friend with you to launch it and you can fly it. I had a friend of mine with me most of the time.
Logged

SANWA SD-6G
Turnigy 9XR PRO
T-copter, "DREAMER" Coro Glider,
Easy* II, X525 Quad, Old Fogey
hercules Quad copter
Thundertiger SparrowHawk XT
There are more planes in the sea than there are ships in the sky
 

Read
« Reply #14 on: January 12, 2017, 01:01:00 PM »
swapnilnimbalkar
Plane Lover
Senior Member
***

Reputation Power: 2 
swapnilnimbalkar has no influence.
Offline Offline

City: Thane
State: Maharashtra
RC Skills: Beginner
Posts: 157
Join Date: Nov, 2016



Yes i will give it a try next time. Thank you.
Logged
 

Read
« Reply #15 on: January 12, 2017, 11:11:52 PM »
bmblb
Plane Lover
Forum Veteran

****

Reputation Power: 5 
bmblb has no influence.
Offline Offline

City: Bengaluru
State: Karnataka
RC Skills: Intermediate
Posts: 312
Join Date: Apr, 2010



Thank you so much for the input.

As per my understanding the prop was fixed at suitable position with little bit of downthrust.

I did test glide with it. It did glide well. As far as throws are concerned I did not calculate it. Will do it n tell you.

Yes the horns are fixed correctly.

I will increase the wing span, currently it is 40". So I will add 6" on either side with little bit of dihedral. Total will be 52".

I am afraid of hand launch thats why i did the landing gear and all. Also adding landing gear corrected my CG.

great! so you know the checklist.

your wing actually looks quite good....and I am sure the ailerons operate opposite direction. adding the tips is a good idea...the ideal wing planform for a first plane.

...can you describe the first flight ? is there any serious damage? including the total weight(AUW) helps in getting a better idea of the plane....

 from what you say and looking at the pic, theres no reason for it not to have a decent flight...

good luck
Logged

"The Flight Of The Bumblebee"
 

Read
« Reply #16 on: January 14, 2017, 12:22:03 AM »
swapnilnimbalkar
Plane Lover
Senior Member
***

Reputation Power: 2 
swapnilnimbalkar has no influence.
Offline Offline

City: Thane
State: Maharashtra
RC Skills: Beginner
Posts: 157
Join Date: Nov, 2016



Hey Hi.

The wing is actually quite good with the load bearing capacity. I put a dictionary at middle of the wing and held it near tips i mean one tip in my hand and other one was held by my brother.

It did not deteriorate at all, neither bent. The dictionary weight about 1100 gms. I think it has more load bearing capacity but its worthless to check as my plane AUW was 770gms including wing. The wing is 180 gms in weight.

Yes the ailerons move in opposite direction.

The nose of the plane is very low density thermocol i.e. crush zone. Its about 3 to 4  inches in height and width according to the profile of the plane and tapered towards front.

About the first flight:
I put it on the runway. Which is isolated road on a big ground you can say cul de sac.
Gave throttle, it started moving, whole time my thumb was tx for full up elevetor it didnt fly just veered in right direction towards some big stones.
Second try was same but this time it veered to the left and hit a stone so hard that the front thermocol (i.e. crush zone) was totally destroyed, saving my plane. Just the motor mount which was secured with two sided tape came out of its position.

By the time lot of kids had gathered around me, so i left the place along with my friend, thinking it might hurt someone. You know kids might just put their finger to check how fast the propeller is spinning.

May be this upcoming Sunday or next one I will give it a try.

Thank you.
Swapnil Nimbalkar
Logged
 

Read
« Reply #17 on: January 15, 2017, 01:10:02 PM »
swapnilnimbalkar
Plane Lover
Senior Member
***

Reputation Power: 2 
swapnilnimbalkar has no influence.
Offline Offline

City: Thane
State: Maharashtra
RC Skills: Beginner
Posts: 157
Join Date: Nov, 2016



Hello everyone.

The hand launch method did work. It flew.
Unfortunately I did not capture any video.

Thank you everyone who helped me.
Logged
 

Pages: [1]   Go Up
Jump to:  

Related Topics
Subject Started by Replies Views Last post
KF Airfoil
RC General Topics
ankur 7 3648 Last post January 01, 2012, 12:58:51 PM
by AEROVISHWA
Airfoil for trainer « 1 2  All »
Beginners Zone
azhaguvel 36 14261 Last post February 28, 2012, 11:37:40 AM
by rajeshbhanushali123
Airfoil Design
Beginners Zone
rajeshbhanushali123 8 3881 Last post May 08, 2013, 06:13:55 PM
by girishsarwal
How to build simple airfoil
Beginners Zone
RCNeil21 0 1041 Last post May 24, 2013, 10:47:15 PM
by RCNeil21
My blubay 42" kfm3 build log. « 1 2  All »
Electric Planes
rcrcnitesh 39 4900 Last post October 15, 2013, 02:00:02 PM
by rcrcnitesh