mvigod

I am doing a review on the Sportsman Aviation Paramount 52/70 and I am thinking of doing this one as my first major (read big) conversion to electric. Taking anything on of this size the first time with all the unknowns is certainly intimidating not to mention I have to document the entire thing for the review!

So in true RCU fashion I'm going to call upon the members to graciously help me out along the way on this project from the selection of the motor/esc/batt combo to the install if necessary.

A link to the plane and its specs is here:

http://www.hobbypeople.net/gallery/127559.asp

I did the larger version of this plane as glow and it is awesome. The review is in the RCU magazine. The build would be identical except when it comes to the power plant plus the 52/70 is the baby brother to the Paramount 90 I reviewed.

So starting out I need suggestions on motors/gearboxe/esc/prop/cells. The combo must give full unlimited 3D and vertical. No compromise.

I think the biggest prop I can get on this is 14" and maybe 15" but the 15" might be pushing it. So does anybody think that I need to get a taller custom landing gear to raise this plane up for a bigger prop?

Here is one suggested power combo:

Motor: Hacker B50 9XL
Gearbox: 5.2:1 in-line
ESC: Hacker 77-3P
Prop: APC 15x10 e-prop
Cells: 20-cells of CP2400 NiCd
or ThunderPower TP8000-5s4p "Dynamic Power" LiPo pack


thanks everyone.

Matt Kirsch

My Feedback: (21)

Marc,

20 CP2400 cells = lead sled

That's "old school" electrifying. I'd say use an AXi, but then I'd sound too much like Greg Covey. I think you could run a 4120/14 on 4S4P (Thunder Power or Kokam 1500s) with a 14x10 prop, though. Even better, 4S2P of the 20C Kokam 2100s when they finally come out. Almost 600 Watts on a plane that will weigh about 5 pounds.

Regardless of what motor you choose, I'd say 600 Watts is your starting point. 12 cells or 4S LiPoly at ~50 Amps, or 16 cells at ~38 Amps. Pick a motor that can handle it, and the biggest prop that'll clear the ground. In between, if necessary, a gearbox to make it all work.

Even 12 CP2400s will be a LOT lighter than 20. Your flight'll be pretty short, but performance will be phenomenal, IMHO.

Mike Parsons

Alot depends on the clearance you have for the prop, but I would think you could easily swing a 15X10 at the least. A Mega 22/30/2 geared 3.33:1 swinging a 15x10 on a 4S3P would yeild you over 1:1 thrust ration at 50 amps. If a 16X10 would clear, I would gear it a bit depper at 4:1 with the same pack and you can easily get to 1.5:1. I t really depends on how you want to fly it. If you want Acrobatics with incredible verticles, I would go with the first mentioned. If you want 3D, I would go with a deeper ratio and 16" or 17" prop. Mega's are incredible motors that hold their own against Hackers and are all too often overlooked. With this setup and maintaining lithiums, you should make it right around 5.5 pnds saying that their published weights are correct. I can upload some video of my Sukhoi on this combo that demonstrates the power.

For Pattern/Sport/IMAC
Mega 22/30/2
MEC superbox 3.33:1
APC 15X10
4S4P of 8C or 4S3P of 10C Thunderpowers
UBEC

For more 3D
Mega 22/30/2
MEC Superbox 4:1
APC 16X10
4S4P of 8C or 4S3P of 10C Thunderpowers
UBEC

For serious 3D and slower flight
Mega 22/30/2
MEC Superbox 4.6:1
APC 18X10
4S4P of 8C or 4S3P of 10C Thunderpowers
UBEC

-Mike

mvigod

Yes. My goal on this is slower flight and SERIOUS 3D!

Mike Parsons

Then my suggestion is :
Mega 22/30/2
MEC Superbox 4.6:1
APC 18X10
4S4P of 8C or 4S3P of 10C Thunderpowers
UBEC

Matt Kirsch

My Feedback: (21)

Notice something about the recommendations so far? They all involve the SAME battery, a 4S LiPoly. Strange? Coincedence? Separated at birth? Maybe not. All the recommendations are simply different ways of applying the same amount of power to the air.

Mike Parsons

And being cheap 4S is less expensive than a 5S.

Matt is correct. As long as the batteries can handle the amps...the prop/gearing combinations are endless.


However...I am not completely ready to rule out the seperated at birth theory

Here is a video of the flight tests with the UCD 46 on the below setup. I have since changed the prop to an 18X10. I was extremely nose heavy and on the backside of a 14 cell 3300 pack in this flight so I was fighting to maintain the hover.
Mega 22/30/2
MEC Superbox 4.6
17X10
4S4P TP 8ah
[link=http://epowerflight.com/video/UCD.wmv]video[/link]

-Mike

mvigod

so would the best strategy be to get a custom landing gear made to raise the height of the plane so I could get a larger prop on this bird? from what I recall the 15" prop on the 90 version of this plane was cutting a lot of grass so I had to go 14". Would an AXI allow me to get away with a smaller prop but still get good performance?

Greg Covey

Marc,

Much of what you decide to do will depend upon your review goals.

When I am reviewing a new plane but decide to use electric power instead of the intended glow power, I try hard not to change any of the plane design. The manufacturer will more likely prefer to see the model with all its external parts intact.

Sometimes, review goals for the manufacturer conflict with other personal goals. Simply converting this model to electric power is one example. In these situations, I sometimes try to offer a choice for the reader by adding a sidebar or upgrade section after the review is completed. Once the review is complete, I feel free to add bigger changes to the design.

mvigod

greg,

good advice. I'm going to measure the approximate clearance with stock gear today to see what the prop clearance limit is