How about a Goldberg Tiger 2?!

[John Z]

Having maidened my Tiger 2, I can only say:Why didn't I do it sooner?
I bought this plane pre built from a friend a couple years ago. I flew it first with an Astroflight 25G and 16 cells but had problems with the ESC as it couldn't handle the battery pack. I set it aside and waited until I had a brushless power system to install.
I also installed separate aileron servos instead of the single unit. I also installed the elevator and rudder servos at just ahead of the stab. For servos I used HS-85MG. The receiver is a Hitec 555.
I covered the model in Ultra Cote transparent violet and yellow.

Okay, so here are some stats:
Powerplant: Mega 2230/3
Gearbox: MEC 2.41:1
Motor mount: Esprit Models custom mount.
Prop: MAS 13X8.5 electric
Batteries: 16 GP 3300.
ESC: Castle Creations Phoenix 60 in conjunction with a UBEC for radio system power.
PIlot: Williams Bros.
Weight of plane less batts: 71 oz.
Weight of batteries: 37 oz.
total weight 108 oz.
Measured performance using as Astro Whatt meter:
42 Amps 770 watts 7460 RPM 114W/Lb.
The plane was designed by Dave Patrick and flies like a dream with very little trim adjustments needed. Takeoff was uneventful and required 3/4 throttle.
I am very happy with the performance of this plane with this power plant. I'm sure an Axi 4120/16 would work just as well.

[igno]

Hi John z, nice looking Tiger 2. I am converting a very similar looking plane to electric and was wondering what size glow engine your Tiger would take. Also, If you ever flew it with a glow engine how long were your flights?

[John Z]

Igno, the plane was designed for a .40 size glow engine. I never flew it with one. I got it with the intention of glow power but about that time I was beginning to move away from the darkside....hehehe. John Z

[igno]

The plane I'm building and hoping to convert to electric is a 13+ year old Royal Air 40T and belongs to a friend of mine. I was asking about the flight times because since he already has a brand new in the box(although 13+ year old)glow engine I'm kinda tempted to use it but like you said I don't know about the "dark side". I'd rather go with brushless and lipos. I should have THIS THREAD (http://www.rcgroups.com/forums/showthread.php?t=385574#post4012596) moved to this category.

[flossandfly]

I converted a tiger 2 using the axi 2826/12 with 12X6 prop, CC-45 ESC with BEC disabled. It weighs around 96 ounces (if I remember correctly) and some motor charts say I should expect about 67 ounces of thrust at around 29 amps. I will try to fly it this weekend and report my flight times. I am using a 4s2p 4900 mah battery so at wide open throttle I should get

[{4900 (mah)/1000 (mah/amp)}/ 29 (amps)]*60 (min/h)=10 minutes of WOT.

Hobby lobby has a link of planes they have converted to electric and some of them have video. They have converted the Tiger 2 but used a different motor and battery than I did.

http://www.hobby-lobby.com/glow2econ.htm

[flossandfly]

I tried the tiger 2 (92 oz AUW) over the long weekend and on the first day with the axi 2826/12 with 12X6 prop and a 4s 4900 mah pack. I measured 20 amps at wot ( some charts told me to expect around 28 amps, maybe my altitude of 2400 ft makes a difference) I don't know the thrust but it didn't seem like enough thrust to take off so I didn't try. I put on a 13*6.5 prop (drew 22 amps) and did a long run down the runway and got off the ground but landed right away since it seemed I had too little power.

The next day I bought some new propellers but the guy wiht the wattmeter wasn't at the field. I put on a larger front wheel so a longer prop would fit. I tried a 14*10 but it cut out on the bench. fron there I tried a 13*8 apc prop and the plane took off but had to remain at full throttle. I tried a 13*10 prop that had to stay near full throttle to fly and the engine cut out once after a long time at full throttle.

I want to try a 14*7 prop but the hobby store didn't have one. When I get one and try it I will tell you how it went.

[John Z]

Flossandfly, I don't believe you will ever get enough power and thrust to fly the plane. Remember this is a sport flyer and capable of aerobatics. You will probably have to go to a 6S lipo as I have since then and found the plane really comes alive. I am using 2 3S 4160 Apogee packs in series. I get a solid 10 minutes of hot flying with it . I plan to try some TP prolites next spring with higher current ratings so I can get some 15 or 20 minutes of flying.
You need around 100 w/lb. to get this plane to turn on. It is a very smooth flyer and makes me look better than I really am :D .
Good luck and son't give up. Cheers john Z

[flossandfly]

John Z, I think you are right. I have the glow engine from this plane still and have to decide if I should spend the $$ for more batteries or put the glow engine back in. My battery pack is made of 4 apogee 2s 2480 mah packs connected in parallel first then the 2 parallel packs connected in series. I could get 2 more 2480 mah packs and connect in series with my current setup but would increase the weight by 310 grams (11 ounces) and cost more in batteries.

Since this was an experiment I only have one set of batteries so even if I bought more batteries to get the Tiger 2 flying happily I would only get one flight then have to wait for batteries to cool then charge.


I think I will look for a smaller plane for this motor/battery combo. If lipo prices drop then I will revisit the .40 size conversions.

[hermperez]

the 2826-10 works very well with a 4s pack, reaching over 600 watts with an 11*6 prop.. so I would think the 2826-12 will need a much bigger prop to reach that level of power, around a 14" prop.. and of course your packs have to be able to handle the 40amp currents without cutting out. I dont know why it cut out with the 14" prop, probably a pack/wiring/connector limitation. Here you can see test results with your motor:

http://www.flyingmodels.org/motortest/brushless/model_motors/axi_2826-12.htm

You will need a 6s pack for that plane/motor or a different motor.

4 cell lipo pack is similar to a 12 cell nicad/nimh pack..

Herm

I tried the tiger 2 (92 oz AUW) over the long weekend and on the first day with the axi 2826/12 with 12X6 prop and a 4s 4900 mah pack. I measured 20 amps at wot ( some charts told me to expect around 28 amps, maybe my altitude of 2400 ft makes a difference)

[flossandfly]

Hermperez.
The 2826/12 has to work at the upper limits of it's capability to get the Tiger 2 flying so I put the glow engine back in. It did fly but not well...and I only get one flight since I only have one battery pack and it takes so long to charge it.

My battery pack is made of 4 apogee 2s 2480 mah packs. I will look for a smaller plane that diesn't need as much thrust and maybe try to make 2- 4s 2480 mah packs so that I can get 2 flights and charge and cool in between.

Right now I put the motor onto my glider (`47 ounces) with just one of the 2s 2480 packs. It turns the 12*6 prop with enough thrust to fly it.

[colbyweb]

John Z, I think you are right. I have the glow engine from this plane still and have to decide if I should spend the $$ for more batteries or put the glow engine back in. My battery pack is made of 4 apogee 2s 2480 mah packs connected in parallel first then the 2 parallel packs connected in series. I could get 2 more 2480 mah packs and connect in series with my current setup but would increase the weight by 310 grams (11 ounces) and cost more in batteries.

Since this was an experiment I only have one set of batteries so even if I bought more batteries to get the Tiger 2 flying happily I would only get one flight then have to wait for batteries to cool then charge.


I think I will look for a smaller plane for this motor/battery combo. If lipo prices drop then I will revisit the .40 size conversions.

How about a 5s1p 4000 mah for $106?? I have 2 of their 4s1p 4000mah packs (and many smaller packs) and I'm very happy with them.
http://www.rc-dymond.com/order_batteries_lipol.htm
You wont get the high current draw you can get from apogees but for sport flying they are great.
-Rick

[flossandfly]

Sounds good colyweb, but by the time I get those batteries to canada they will be much more than $106.00. With new 20 C batteries coming out I am sure that the price of the 7 to 10 C batteries are going to drop a lot. I will wait until it does then will try the Tiger 2 on electric again. (If it is still in flying condition by then...)

[DBono99]

Hi All I just happen to find this thread..I just built and flew my 1st E-plane, boy was I impressed, now I'm thinking some where down the road, to make a 40 size Cloud Dancer an E-plane..But before I tackle that project, I'm going to build a Stevens Aeromodels G-ride 300.

Ok lets get back to CD..I weight my all ready CD it came itr at 88 ozs fully loaded with a GMS 47 and all Futaba gear (5) 3004's servos' and Etc.
Would the AXI 2826/10 or 12 work for my set up..I'm not into 3D or in need of a rocket ship..I just love the looks of the CD..I've already built 2 with many mods to them.My goal is electrify my next one..I'm thinking I may 400 watts/72 watts/lbs.

Please let me hear your thoughts/suggestions on this project.

Thanks Dan

[DBono99]

Hi Again Here is a pic of the 40 size Cloud Dancer.

[feathermerchant]

The 2826 may be marginal if you'll only have 72/lb
You might want to consider the 4120

[DBono99]

feathermerchant With the type of flying i do 72 should be more then enough w/lbs..I was usijng that 72 as guide..I;m sure the 2826/10 or 12 can produce more watts..But at higher amps.

Any way It's just starting point for me..I have to build the park flyer 1st, Then when it warms up again here in NJtackle the 40 CD..I can probably build it light also..

Thanks Dan

[feathermerchant]

Build it light is the key. Don't need all th eply in the nose for the big thumper.
Lighter means smaller and cheaper power system too.
Weather here is sunny and ~71deg with no wind. Too bad I had to work all day.
Just come down here and fly. It's usually pretty nice till Christmas.

[DBono99]

Hi That 72 watts per pound should be enough..Besides that just a starting point.. I know the 2826/10 can produce more amps thus more watts.

These are Jim Bourke #'s he did a 40 size Coud Dancer.
65-75 w/lb Easily loops from level flight. More im pressive aerobatic performace..

75-100 w/lbs Extended vertical runs.Unlimited aerobatics..

So then 72 should do just fine. At least I think it would..

Thanks Dan

[hermperez]

400watts is a light load on the 2826-10, prop it for 600-700 watts, of course dont peg the trottle for 10 minutes or the motor will burn up.. it is a good light motor for a cloud dancer..in a tiger II the plane may never balance, better to use an axi 4100 series in a glow conversion.

Herm

[DBono99]

Hi I was just thinking that 72w/lbs should good enough..The 2826/10 with the right prop, will get up to 600 watts,I believe?

Dan