Organ donor

[tandemairbike]

A flying buddy of mine recently sent his Art Tech 182 to the promised land ( I guess even foam becomes brittle in the cold,) and donated the internal organs to me. He has been trying to get me to do an EP plane for ages and says I have no excuse now. Well I could come up with a list of excuses, but seeing as he was so generous, I am giving it a try.

I'm doing it on the sly so I can show up at the field with it and surprize him and so I am going to need help from you guys.

I suspect that these batteries get hot while the motor is running and will require provision for cooling. How much air intake area and exit area is required for a 480 direct drive motor with 8.4V 1000mah NI-MH battery?

I have heard that some ESCs interfere with the receiver. What steps need to be taken to deal with this. Does the ESC get hot when motor is running also? Can it be wrapped with foil to block interference to the RX?.

I have drawn and started the airframe but before I go too far I need some of the above info.
Any and all help will be appreciated.

A great day to all,
Tandy

[tandemairbike]

Well, I started the darn thing.
Got some of the bones stuck together.

My first electric powered airplane and I am finding my way through the wilderness.

Here are a couple of photos of the earliest stages.

Would like advice on cooling air intakes and exits and position of ESC in relation to Rx.

Thanx in advance,
Tandy

[tandemairbike]

Spent a couple hours this evening carving and sanding nose block and motor compartment hatch. Also started adding built up tips to the pair of vintage Ace foam wings I am planning to use.

I hope I have enough air intake for cooling. I plan to leave the first bay between crossmembers behind the wing on the bottom of the fuselage open for air to exit. Does anyone have any better ideas?

[tandemairbike]

My son and his wife borrowed my camera to take pictures on their vacation so I have been unable to post pictures of the progress I am making with this project. I should have the camera back this coming weekend.

I haven't received any input here regarding cooling of motor and batteries and ESC interference with the receiver. I never did see the installation in the foam plane that these components came from so I have no idea of the mounting position.
So far I have just done what seems logical.
I'll post some more pix when I can.
This is not a fancy plane, just a test bed. It will be sort of a chubby Ugly Stik with slightly smoother lines. I am trying to concentrate on keeping the weight down. I also made the fuselage somewhat wide to get my hands in to install all the good things. Maybe if this electric thing takes hold of me I'll work up something classier.

[tandemairbike]

I got my camera back this morning so I took some photos of the nearly finished product.
With all equipment on board it weighs in at 21.4 oz as can be seen on my digital scale in the photo below.
Wingspan is 38 3/4 inches, chord is 6 1/2 inches which gives a wing area of 251 7/8 square inches. Can anyone tell me if this wing loading :confused: is in the ballpark for the 480 direct motor. As a glow engine flyer this seems okay but you guys that fly electrics would know better if this is going to work.
Comments please.

[PipesCS]

I am very inexperianced in can motors but I believe that it will fly but may be a little under powered. I will look forward to your first flight.

[tandemairbike]

Thanks for the reply PipesCS.

I will be satisfied if this works out to be a Sunday sport flyer as I am not too much into hot pattern ships any more. As I get older my eyesight and reflexes aren't what they used to be. I used to love to burn holes in the sky and make high speed low inverted passes back in the day but now I enjoy a more relaxed style of flying.

Yesterday's high temperature here was +23 degrees F. so It will be spring at the earliest before this plane flies. At least two months.
We'll see what happens then.
From the photos and text, do you think that I have sufficient cooling?

[Gerryy]

Tandy, your model looks like it should fly nicely. With your 12.22 oz./sq. ft. wing loading, your model should have a nice, moderate landing speed. To estimate performance, you can use the 50 to 60 watts per pound formula for gentle easy flight or the 70 to 75 watts per pound for better sport performance. You will need a whatt meter or something similar to check your voltage, amps and watts.

The Speed 480 motor I think, draws about 10 to 12 amps (not really sure,) so you multiply the amps by the voltage of your battery pack. Say an 7-cell Ni-CD. that would be 8.4V x 10 amps = 84 Watts or 100.8 watts @ 12 amps. take the watts and divide by the weight of the model in pounds

84 watts / 1.3 pounds = 64.6 watts/lb.
100.8 watts / 1.3 pounds = 76.9 watt/lb.

You can adjust the amps your motor pulls by the prop size you use. larger props will pull more amps which will increase watts. But the rule of thumb is to find a good prop for performance and then increase volts to increase watts! Add a cell to the pack!

This is why running a 3-cell Lipo pack 11.1V increases performance of most planes. the battery pack provides more voltage and reduces over-all weight. Just make sure you keep an eye on the amp draw and match it to the type of Lipo pack you use. But also, the increased voltage can shorten the life o your motor. matching motor, ESC and battery specs is always important for long lasting power systems!

As for motor cooling, make sure you have an air exit somewhere for proper airflow. The intake opening looks fine.

Hope this helps!
GY

[PipesCS]

What battery are you using?

[tandemairbike]

Thank you Gerryy for the input.
I have an opening on the bottom of the fuselage behind the wing that measures 2 1/2 inchs x 3 inches. This may seem large but i allowed for the fact that the airflow would be obstructed by the batteries and the servos on the way out. The prop that i am using is what came with the gift of the equipment and is probably not optimum for my airplane. It was originally in an Art Tech Cessna 182 foam airplane. The dia. and pitch are not marked on the prop. It measures 7" dia but I haven't a clue what the pitch is.

To answer your question, PipesCS, the battery is 8.4 volt 1000MAH NIMH.

[tandemairbike]

Voila!
I believe I found the reason for the crash of the Art-Tech Cessna 182 which resulted in my owning the Working parts.
When I first plugged in the battery and started the motor, It ran for a few seconds and stopped. As I removed the front hatch to find out why, the motor started again and the servos all contracted St. Vitus Dance, then all went dead again.
Turns out that the wires going into the battery plug are all loose and afloat.
The staked pins are supposed to be pressed tightly into the plug body but these worked loose and intermitently lose contact.

If your flying A cessna 182 or any other plane by Art-Tech it behooves you to check these plugs and replace them if you have not already.
I will be ordering some Deans connectors for this system.

[PipesCS]

I have the westwind drawing coming along and will be off next week with a trip to maryland the week after that. I would hope to have your kit cut and on the way the week after that.

[tandemairbike]

Sounds like a plan.
Thanks for the heads-up.
Tandy :D

[tandemairbike]

Sun is out and it's warmed up to 30 and climbing.
Can't get into the flying field yet as we are not allowed to plow the snow in the winter . It may tear up the hayfield.
So I took her out to taxi test her on my front lawn.
There is a frozen crust on the foot of snow there. The warm March sun has softened the top of the crust so that there is about 1/4 inch of soft wet snow on the surface.
The plane has enough power to start moving by itself in this stuff and I feel it has plenty of power to fly.
Ground handling is very good and controlable in the 15 to 20 MPH gusts out there.
Also range tested the radio. Antenna down I have a solid seventy five feet. At eighty feet the servos get nervous. This seems about right. I think.

[tandemairbike]

Hre are sme more shots.

[PipesCS]

Morning Tandem

I am offloading the drawings for the westwind into my travel computer and will have the kit ready to cut by Friday. From past experience I am thinking this will cost you in the 30.00 bracket for John to cut it.

He charges $1.66 per minute to cut and fair prices for the balsa and ply materiels

I will also have a set of the drawings burned off and mailed to you while in Maryland.

[PipesCS]

Photos like these make me glad I retired to Alabama. I have seen 3 snows since 1995 and then only for half a day as it melted off by lunch...

[tandemairbike]

If I had my way I would be living in Yuma or Ft. Huachuca,AZ.
My wife's family is all here in New England and she doesn't want to leave them.
I am the last of my family so she and her's are all I have so I guess I'll be here for the duration.

[PipesCS]

How do you even know about Ft Huachuca. Must have done time in the Army in the intel field...

I just finished your redraw of the Westwind out of the 1958 M.A.N. I scaled every thing off the 1.75 diameter main wheel as the original article gave no information on the sizes exept the tire size. I will have you a print done at a local shop tomorrow which should not cost more than 6 dollars. I would post a copy here but the jpeg is too large.

I have marked the plans for your use only and that they are not for resale to protect the original designer. His name is the only one on the plans with a note that I redrew from the original magazine.

I have the parts ready to send to the kit cutter. There are 40 parts total and the only liberty I took was to notch the lower fuselage sides and put tabs on the frames to help you line everything up when gluing it together...

I counted parts on a Curtis Robin I did that had cost 27.00 with shipping and handling. It had 32 parts so yours will be a little higher as you have a few more ply parts...

Do you want me to go ahead? If so notifiy me with a private message on this site as my e mail is down. Please include your shipping address as I will have him ship direct...

[tandemairbike]

Back in the late sixties and early seventies I owned and operated a long distance moving van leased to a major van line.
I moved three military families from the Washington/Alexandria area to the Ft. Huachuca area and a retiring AF colonel from Limestone ME to Yuma.
The Air force paid to move his 26 inch snowblower to Yuma. He said he was going to Paint it bronze and place it on his front lawn.

Proceed with the lazer cutting of the Westwind and advise paynent method so I may make immediate payment.
Ship to My business address:
Lantruk
523 Bond Spring Rd.
West Newfield, ME 04095-3216

I would really like to get a kit for the Curtiss Robin you mentioned at some time in the future.

By the way, did you receive the CD that I mailed to you?

Thank you and have a great day.
Tandy

[PipesCS]

Short kit is being cut and I have asked John to give me a price on printing you a copy of the plans and sticking them in the box.

He will ship direct to you with an invoice in the box... I would hope with the plans and everything it would be around 40.00

Have you flown the electric yet?

[tandemairbike]

Thanks for the heads-up on the kit. Very reasonable.
Haven't flown the electric yet.
I'm waiting for site access, calm moderate weather and a good cameraman so I can post some flight pix.
Tandy

[tandemairbike]

After several delays and postponments this bird should fly on the 19th of Aug. at the club picnic and flying session.
After running this thing a few times I did not feel that it was putting out an abundance of power with the NI-MH pack so I have A Li-Po pack and charger ordered (here I go getting immersed in this electric stuff) and they should be here in time. This is all new territory to me and I don't even know if the ESC that came with this outfit will handle Li-Pos or not. It is covered with black shrink wrap with no printed information at all.
No matter, this has dragged on long enough. It will either fly or explode, either of which will probably be spectacular.

Tandy

[tandemairbike]

I received the Li-po battery pack and charger today.
I installed the pack in the plane and fired it up. Certainly a world of difference.

It is a three cell 11.1 V. 1000 MA pack.
The charger is a two or three cell balance charger that automaticly shuts off when the battery is fully charged.

I no longer have a tach so I can't make comparisons but the increase in RPM is somewhere between My My and Hot Diggety Dam, and the ESC seems to be working fine with no excessive heat buildup. Motor life will probably be shortened but they still make motors.:)

I will feel more comfortable now when I throw it for the first time. Now I just hope these old eyes and reflexes can keep up with it.

Tandy

[tandemairbike]

After more than a year of waiting I finally maidened the Watts This.
Weather man said sunnywith high winds for today.
6:30 AM it's dead calm so I got ready. At 7;00 AM I loaded the Watts This and the Westwind into the car
and headed for the field for their maiden flights. Both planes being ready for about a year now.
Today is the day.

Got to the field and range checked both airplanes, Good to go.
My son was with me with his digital camera for photos. took about a dozen and we managed to get one
useable one.

Airplane flew off the bench with only 2 clicks of left trim required. right wing panel a mite heavier than the
left probably. Needs a little more elevator deflection but not critical. All in all a satisfactory flight with nice
soft snow to land in with no damage. All this with the Ni-MH battery.
Flight time 6 minutes.
Second flight with LI-PO battery. Burns up the sky, ticks off my photogrspher and has excellent elevator
response, cool roll rate and ,while not limitless straight up performance, climbs like a homesick angel and
spins like a trooper.
I willtry to get some better flight photos at some time in the future.