Sig Senior Gas to Electric conversion.

[GoingVertical]

Hi everyone!

A club member offered me his Sig Senior for free but it was setup for gas and I'm wondering what powerplant setup will get this 80" inch trainer up.

It's beautifully built-he even built ailerons into the wing!

I don't want to get into gas so I'd like to get an idea how much it's cost to convert or just go to RCUniverse and try to find one already built.

Too bad it's not a senorita......

Thanks...Greg

BTW..he complained the LG was to weak; has anyone used a CF LG on this?

[RMS]

Check the electric conversions thread. I am pretty sure this has been done a few times. Regarding the LG. I have built several as taildraggers using Aluminum or the Klett landing gear.

[Bill Hawthorne]

These may give you a few ideas for your project...

http://www.rcgroups.com/forums/showthread.php?t=330307
http://www.rcgroups.com/forums/showthread.php?t=376759
http://www.rcgroups.com/forums/showthread.php?t=233468
http://www.rcgroups.com/forums/showthread.php?t=248081

[airorv]

We have 2 electric Senior's in our club. Both fly just great.

The ARF version has an AXI 4130/20 on an 8s2p 4000 pack, I think a 17x10 prop. It is really pure stock. I haven't seen a glow powered version that flies better.

The second is kit built that is a bit heavier. It was originally beefed up for a 120 four stroke engine. It now has a Hacker A50-16L and a 9s2p 4000mah pack. I think we have a 16x10 prop.

Both are overpowered but at reduced throttle they are very nice.

[GoingVertical]

You are a fountain of wealth!

I'll sell some blood to buy that massive lipo this is a heavy built with custom ailerons and heavy pneumatic LG.......It's the old rubber band attached wing version.

I'll see how much the lipos are...

I can also slap a Thunder Tiger .90 in there...my buddy has one thats new that he'd give me but I hate nitro!...FIre! :eek:

Nonetheless thanks for the links and configs....Greg :)

[BEC]

Well, lessee.....back in the old days (pre-affordable-brushless and pre lithium batteries) one would do this with anything from a geared Astro cobalt 25 on 14 sub-C NiCds on up to, say, the 60 on 28 cells. Lighter would be more in the spirit of the airplane. So - to put it another way, from about 400W on up.

These days it's really easy to do......

[rcjake]

My Kadet SR arf is powerd with a PJS 3D 3000 Brushless Outrunner Motor, Castle Creations 80amp ESC and a Poly RC 3700mAh 4s lipo pack. A seperate 4.8v battery pack was used for the rx.

The Kadet flies great with this combo. Floats will be added soon and it will be attending our upcoming float flys this fall/winter in addition to flying from the ground.

Jerry

[Smash McCrash]

If you are just looking for trainer like performance, the club prez has one with an EFlite power 60 on 6S A123 M1's. Not sure of the prop, but he seems to like it. I haven't seen it fly, but I can't see it being overpowered (like a 3D model) on that setup.

Mike

[tone]

Mike -
A 4130/16 or Power 60 on 6S with a 17x8 will make the Kadet fly like a true sport model/nearly 3D. It will hover a bit, but not really pull out vertical, has to fly out. A buddy flies his with a 4130/16 and an 18x8 (taildragger setup). i don't reccomend this setup much due to the 67 amp draw wide open (1600+ watts 160 watt per pound), but he has flown it this way for over a year and no motor problems at all. He only uses wide open for a few seconds then floats it for a while. 3/4 throttle to climb out quickly to soaring altitude..
I am building one now and will do the same (except the prop, maybe). A 17x8 would be in the 60A/60sec tolerance of the motor.

[hermperez]

I have 3 Kadet Seniors now, been flying many different electric ones since 1990 or so.. all you need is about 700watts of power and dont change anything, the design is perfect as it is. It is a 40 size plane, but people slap 60s in them.. does not go any faster, just climbs quicker.

this motor:
https://www.unitedhobbies.com/UNITEDHOBBIES/store/uh_viewItem.asp?idProduct=4907

this esc:
https://www.unitedhobbies.com/UNITEDHOBBIES/store/uh_viewItem.asp?idProduct=2062
or this one:
https://www.unitedhobbies.com/UNITEDHOBBIES/store/uh_viewItem.asp?idProduct=2166

this motor mount:
https://www.unitedhobbies.com/UNITEDHOBBIES/store/uh_viewItem.asp?idProduct=5283

this battery:
http://www.unitedhobbies.com/UNITEDHOBBIES/store/uh_viewItem.asp?idProduct=4130

or maybe this one:

TrueRC 4000mAh 18.5V 5S1P pack CALL
http://home.comcast.net/~truerc/ready_pack/ready_packs.htm

[hermperez]

and a 13x10 apc electric prop, 40 amps, 700 watts, about 6lbs of pull.. about 20 minutes duration or so

[8kasl]

Overpowering the big "K" is not necessary at all.They will ROG and fly just fine on as little as 40W/lb.I built a Kadet from a kit and modified it to haul a 2.5lb. video camera 3 yrs. ago and it weighs 10.5 lbs.without the cam.Span increased to 86",fus 3" wider and 3.5" taller,tail dragger,Poly-plug-in wing outer panels,fiberglass cowl aluminum main gear(8oz.),Axi 4130/20,5s 6750 pack,20/13 prop.Normally I read around 850W. max,but flew at 1/3 throttle.One spring day this year I noticed the wattmeter read only 445W. on run-up and figured that the pack was too cold and 2 yrs. old,but decided to fly anyway.I was amazed to see how well it flew--low on power yes but it climbed out at around 15 deg. and cruised around just fine.The pack had been stored in a shop outside all Winter here in Colorado at 8000' where I live=it goes below zero allot.I believe that an AXI 2826/10 or equivellent would pull a stock 6 lb. Kadet around as a trainer on 3-400W.Just my 2c.

[8kasl]

BTW, I forgot to mention that I call the big "K" the "Widebody Super Kadet.

[hermperez]

My kadets are all around 4lbs RTF not including the batteries.. they were designed to fly using 18-24 of the big nicads.. with A123 lipos or standard fireball lipos they would come in at around 5-6 lbs and the 2826 is really all you need in terms of power.. duration is too much :) .. the question is can you run a 2826 at 500-600 watt levels for 10-20 minutes?.. long duration flights really tend to overheat motors.

Fried many astro 40 cobalt motors in Kadets. Check out my web site. there is a link to Kadets towards the bottom.

[8kasl]

I suppose if you ran at WOT or close at 5-600w you'd burn the 2826 up,but why fly a K at that level.Were flying a Trainer here unless I missed something.I have 4 2826 series and have tested the 2826/10 to 59A. and 864W. for 5 secs and not even hot,but getting warm,so I'm thinking you could run continuous at around 400 or a little less without damage with good airflow.BTW,Herm,getting the senior in under 5# is impressive-good work.Did you build from plans or?

[tone]

here is my buddy's Kadet Sr. on a 4130/16 and 6S 5400's. I think he is spinning an 18x10 or 18x8... it weighs about 10 pounds.
The weights listed by guys above are not from the ARF that much is certain. The kit components weigh more than 6 pounds. No glue, no servos etc...
anyhow, the batteries a absolutely new so the power will continue to go up and this is his maiden of this model so the aerobatics are well within the envelope. :)

http://mhowell.electricdrones.com/07-01-07.wmv

I am building mine exactly the same as his.

[hermperez]

The first one was built from a kit at swap meet that my club held, a demo.. everybody worked at it.. the next 20 or so were built from plans :)

But the only changes we did was conversion to tail dragger and sometimes leave the forward sheeting off.. all that would save maybe 6oz if that. The kit as designed builds ligh but many builders have a tendency to beef it up.. I have seen the arf and it looks just like the kit. If you have an arf unbuilt please weigh all the components and let us know.

First one was 6.25lbs using 18 of the panasonic 1700 scrc cells, 32oz I think for the battery pack, astro 40 cobalt geared.. 3 channel airplane with no ailerons. Batteries were light but did not last more than 50 cycles.

BTW,Herm,getting the senior in under 5# is impressive-good work.Did you build from plans or?

[tone]

yeah, i did that when i first got the model, because i had been ragging on my buddy because the box says something like 6.25 to 6.5 pounds RTF.
The ARF has Ailerons, but of course that shouldn't add 3 pounds to the dry weight.
I will be making it a taildragger as well, it just looks so much better, both on the ground and, in flight.
anyhow, i think it was over 6 pounds just for the stuff in the bags.
For a while, he was flying on 2 3S 4200 packs and that was only 21 or so ounces for the whole battery setup. The motor and mount are about a pound which is about what a .40 weighs, i think.
The ARF is definitely not like the kit in terms of weight. I don't know why.
The one i am building will be the third ARF i have dealt with and all are coming in around 9-10 pounds. My most optimistic (wildly) estimate was 8 3/4 pounds, and i think that was a pipe dream.

I would pay to get one strong enough to fly the aero stuff, at 6 or 7 pounds.
Maybe i should look into the kit. The ARF is so convienient and, considering the price of the kit, a bargain! Not many planes of this quality for around 200$.
But the 2.5 - 3 fewer pounds would be something astonishing.

[hermperez]

Have you seen this one?, what does it remind you of?

http://www.airborne-models.com/html/productdetails.asp?ProductID=39

[airorv]

tone,

I have to agree with you. I put the electrics in an ARF Senior and it weighs well over 9 pounds. It flies very nicely with an AXI 4130/20, 17x10, and 8s2p 4000 lipo. Of course lighter is better but I don't know how someone can get one done under 6 pounds.

Way back I had a kit built Senior that had an Astro 40 and 21 cells that weighed just under 9 pounds.

I must use heavy glue or something.

[tone]

Have you seen this one?, what does it remind you of?

http://www.airborne-models.com/html/productdetails.asp?ProductID=39

Yikes that really does have a striking resemblance. :eek:

airorv -
I have long heard the kit ones are considerably lighter than the ARF, but really, 2.5 pounds is a lot of difference. I don't doubt Hermperez at all, i just wish i could build. :)

[hermperez]

Ok, just weighed the one that most resembles stock, RTF with a heavy Dewalt drill motor and a homemade belt drive:

4lbs 3oz, not including power batteries, usually 18 cell 1800scr pack, 39oz..

So there!.. no sheeting, no ailerons, two piece 80" wing with working struts, detachable stab, 2 regular servos, regular receiver.

Does the arf sheet the leading edge of the wing?, the kit does not.. also when I make mine with a two piece wing all the plywood and dihedral braces are not used.. the wing loads are carried by the working struts.. the wing root ribs just pivot on the fuselage wing center section. Like a real Cub for example.

We spent a lot of brain power to optimize this design for electric flight in the day of heavy nicads, and we did not compromise strength and durability either. I think these were some of the first large electrics that matched and exceeded glow performance.

Check out my Kadet page, it shows the wing mounting method and the unique quick change battery system.

http://home.att.net/~hermperez/ekadetsenior.htm

BTW, I'm a lot older and heavier now :)

Yikes that really does have a striking resemblance. :eek:

airorv -
I have long heard the kit ones are considerably lighter than the ARF, but really, 2.5 pounds is a lot of difference. I don't doubt Hermperez at all, i just wish i could build. :)

[hermperez]

if I remember correctly the Dewalt motor/belt drive were around 16oz, 700watts..

with a modern dewalt A123 6 cell lipo pack, and a 2826 class motor it would come out at 5.5lbs RTF.

[mike5334]

Back in 2002 during those pre-lipoly days, my Kadet Senior was powered by an old 1980-90ish German made hotliner motor turning a 14-7 APC electric prop on 18 sub C cells. RTF weight with batteries was 8 lbs even. Flying time was a modest 15 - 18 minutes of leisurely flying with some basic acrobatics tossed in.

It wouldn't climb straight up ... it didn't need to. I had more fun doing really short take offs, touch and goes, and just about anything else a sport trainer could do. During the first year I had it, the plane won 3 fun fly contests, thermaled, slope soared, and got rebuilt after hitting the limbo pole. :)

The Kadet Senior makes a great electric plane!

[hermperez]

Just came back from the field and had a chance to examine a buddys ARF Kadet Senior, yep lots and lots of lite plywood.. there are a couple of formers under the wing made of lite ply, not in the kit.. and they sheet part of the cabin with lite ply (with cutouts).. dont know what the front of the plane is sheeted with. The wing and tail looked normal, no sheeting there with the difference that the original was intended for rubberbands and had no aileronts. He was flying it with a glow 40 and it seemed a bit underpowered on the takeoff (maybe he did not take off at full throttle?), main landing gear was aluminum instead of piano wire.

[hermperez]

The plans used to be available from Sig, easy to scratch build a new fuselage for the ARF and save some weight.. only hard part is the firewall..

[8kasl]

Guys,This may sound ridiculous but back in the early 90s a few of us Kadet owners used to race the Ks pylon style :eek: It was the most fun and laughs we ever had.The birds are too slow to be nerve racking and because of the drag,they seemed to be limited to around 50 MPH or so.I can't remember ever having a mid-air and pilot skill was the way to win usually :D If I remember right,the only rules were------------engines were limited to 46 2 stroke and 80 4 stroke and the plane had to be built to plans dementions with stock flat bottom foil. Ailerons and tail-dragger gear were allowed. ;) Try it-you might like it!