hello every one
i am new to this forum and have read many posts till now and salute the people who are there to help every one.


i have recently finished my new model which is a f-117 nighthawk and wanted to know which motor and prop to use with it

specifications-

length-87.6 cm

wingspan-66 cm

weight- 550-625 gms (everything included)

please

what

Quote from: prateek13 on May 29, 2010, 10:18:59 AM
i have recently finished my new model which is a f-117 nighthawk and wanted to know which motor and prop to use with it

Can you post a link to where you got the model from (or any link to the same model in online stores) ? 

yes this is the link to the pdf of the plans

http://rcfoamfighters.com/blog/?tag=rc-f-117

That link says a 400 watts motor with 6x5.5 prop.

Guess the weight you posted without motor and battery... so if you consider those also, you will need a motor that can pull around 800gms.  A 400 watts motor should be able to do that fairly comfortably.

And please do post some pictures of the plane !

following Dave Powers, that 2200kv is the sweet spot for Foam Jets:

<Edit: Wow!!! I am becoming accurate!! the Turnigy motor I suggested below is even recommended in the original plan!!>

1. Motor:

http://www.hobbyking.com/hobbycity/store/uh_viewItem.asp?idproduct=7993
Weight: 79g  (kv2350) (not including connectors)
Diameter of shaft:F4.0mm
Voltage: 3-4S Lipoly
Prop: APC4.7x4.25
Thrust: 800g
Power: 480W

(A lil bit lower Kv option from LHS)
http://cgi.ebay.in/RCFORALL-BRUSHLESS-OUTRUNNER-MOTOR-A2217K-6-/150421764528?cmd=ViewItem&pt=LH_DefaultDomain_203&hash=item2305d5f9b0#ht_2282wt_911

2. ESC : (60Amp)
http://www.hobbyking.com/hobbycity/store/uh_viewItem.asp?idProduct=2166&Product_Name=TURNIGY_Plush_60amp_Speed_Controller

http://www.rcdhamaka.com/index.php?main_page=product_info&cPath=59_95&products_id=275
http://www.rcdhamaka.com/index.php?main_page=product_info&cPath=58_59_95&products_id=471

http://cgi.ebay.in/RCFORALL-BRUSHLESS-ESC-60A-/150411581446?cmd=ViewItem&pt=LH_DefaultDomain_203&hash=item23053a9806


Props:
EMP/MA 6x4 / 7x4


Lipo: 3S / 175-2200mAh 20-30C

i am currently having a bl 2212/6 motor which was mentioned by Dave Powers/Rc super powers in their videos with a master airscrew  6x4 prop and a 30amp esc with a 3s 850mah 25c discharge battery

problem is that the sufficient thrust is not produced

i am looking for an apc 6x4 or 6x5 or 7x4 prop if any one has a spare one please tell

pleeeeeeeeeeeeeeeeeeeeeeeeeeeease!!!!! help
 

Regardless of where you find the prop, be aware that increasing the pitch of the prop can sometimes significantly increase the amps draw (more than 10A in many cases), so watch out for your ESC capacity during such experimentations.

If you are looking for new ones... http://rotor.co.in/prod-list.asp?catid={A2047792-64C2-441B-BF54-92998B72ED37}

use motocalc - google it

I think you can use it online for free (not sure)

it will give you reasonably accurate ballpark figures

I dont know whether you already read my reply , but the Turnigy 2836 motor,for which I gave the link above, should be more than sufficient for your need. Below are some static test data posted by a reviewer:

Prop. Volt Current rpm Power Pitch spd Thrust Efficiency
APC S400 5.5x4.5 10.68V 31.81A 22321rpm 339.73W 153km/h 816.0g 77 ETA.
APC S400 6x4 10.65V 32.36A 21929rpm 344.63W 134km/h 1064.8g 82 ETA.
APC S400 6x5.5 10.24V 39.10A 19685rpm 400.38W 165km/h 869.7g 69 ETA.
APC Sport 7x5 9.87V 42.11A 17605rpm 415.63W 134km/h 1180g 63 ETA.

You can buy the Props you need from RC Dhamaka (Bangalore)

http://www.rcdhamaka.com/index.php?main_page=product_info&cPath=3_48_80&products_id=265
http://www.rcdhamaka.com/index.php?main_page=product_info&cPath=3_48_80&products_id=266
http://www.rcdhamaka.com/index.php?main_page=product_info&cPath=3_48_80&products_id=263
http://www.rcdhamaka.com/index.php?main_page=product_info&cPath=3_48_80&products_id=264

Hope this helps...

actually my father is not allowing me to buy stuff from overseas and tell me to buy it from lhs.
is a motor available to buy from a lhs but of same power and speed?

Due to low volume sales in India, I dont see any motor with the desired specs (@2000kv, 400W) in top most LHS.. the closest match you can get is that from Rcfor all. Put a "Wanted" post in buy-sell and see if some flyer can spare his motor lying unsed. I have one such motor, but it is 3500kv.

3500 KV should also work... just need to find a smaller prop, right ?

Quote from: anwar on May 30, 2010, 01:28:13 PM
3500 KV should also work... just need to find a smaller prop, right ?

surely, but I guess as you increase the pitch speed (Kv) , the landing speed of the plane would increase... may be better Jet  aficionado can answer properly.. me just theory..

landing speed is no problem as i have spoiler in my plane

Quote from: prateek13 on May 30, 2010, 05:08:06 PM
landing speed is no problem as i have spoiler in my plane

I hope you mean Flaps... dont know how (what) flaps would behave on such amazing aerodynamic design( remember, F-117 is on of the craziest wing design).

Nevertheless, if you still want the motor, I can spare it for you on actuals + HC shipping + shipping to your place... I have put bullets on the motor to do static testing but never put it on plane so the motor is NIB.

http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=8480

it is actually a bomb drop + a spoiler not a flap

today night i tested my plane with the bl 2212/6 and a ma 6x4 prop and it worked fine till i know.

i am satisfied with the results put up by the people and request them to continue replying as it will be helpful in future

pics on 31st morning