darren s

My Feedback: (3)

so after all the help i have received from this forum, i thought it was time to give back. lots and lots and lots of research went into my setup and today was the first flight.

the plane is the Fliton Infinity90, Plettenberg 25-12 outrunner, Schulze ESC, 2 Tanic 4900 packs, today i used a 17x10 prop, JR digital servos.

final weight was 8.12 pounds with the batteries. did 1 six minute and 1 seven minute flight today. put back in about 1100 - 1500 mah respectively into each pack. the wind was blowing 15 mph today at least but i could wait anymore.

the vertical performance was on par with my YS 110 powered Zen 90. the 18x10 prop (which i will try) should give me enough vertical to easily get through the pattern sequence i need to fly.

love the no mess, quiet, reliability, hassle free, no fuel, no remote glow drivers to deal with etc..... lots of $$ to output initially. about $2400 Canadian and that's only for one pair of batteries. i need another pair. they run about $500 Cdn for the pair.

i'll try to post some picts.

thanks, darren

nxtdoor

My Feedback: (10)

Darren, great to see you got your plane in the air.

I have been very impressed with the way the plane flys.

Let me know what kind of temps you are seeing on your batteries and motor if you can. I normally see about 140 on the motor and 105 on the cells. I am barely giving the 10s3p cells a workout.

I just got a Focus II arc that I will try my system in also. I plane to make some major changes to the fuse to lighten and make it look a little different.

Jeff

MicroMac

Great looking Infinity and electric setup.
Love the canopy....is it the stock canopy painted?, or have you moulded a new one.
The stock canopy looks cinda.......dull.
If painted what kind of paint did you use ?

eflier

could you tell me how many cells in series please? ?S?P

darren s

My Feedback: (3)

flight update. two flights today. used the 18x10 prop. flew for 7 minutes and replaced 1800 mah. much better performance, lots of vertical pull just found my aileron roll rate a bit slow for vertical 4 point rolls.

all part of the adjustment flights. landing gear is the Bolly Wide gear. the others are too narrow or not tall enough. with the 18 inch prop still have 2.5 inches of clearance.

cells are Tanic 4S2P 4900. i run 2 in series for an 8S2P total. these packs are IDEAL for this plane. i couldn't fit ANYTHING bigger. i have no idea how others. it is a beautiful fit under the belly pan.

the canopy is stock. i painted the inside with aluminum RC car Tamiaya paint. the stock cut of the canopy is way too big so i slowly cut it down till it looked good. used canopy glue and trim tape to make it look pretty.

i use a 5.6 voltage regulator with a 1320 TP lithium for the radio gear. i didn't use the UBEC. i like being able to charge the packs while i fiddle with mixing.

spinner was a custom cut from tru turn. they lightened the back plate for me. kind of expensive and not sure it's worth it.

has some coupling in knife edge which i am working on but hard to trim everything in a 7 min flight. i am taking it easy on the packs for now to break them in and then will push 10 min flights.

lots of fun...... don't know if i could ever go back to glow.

darren

darren s

My Feedback: (3)

ok, i thought i'd share an update with those interested in this airplane. it's been about 20 flights now and i have learnt a bit more about electrics so i can share some numbers.

i bought a watt meter so i can now adjust things without having to take someone elses word. the batteries are Tanic 4900, there are 2 packs of 4S2P. see pictures. i started flying with the 17x10 prop which drew 36A and generated 1120 W of power. the plane flew nice but lacked a bit for vertical manoevers.

next was the 18x10 : 41 A draw and 1210 W of power. much better vertical power but i realized that at 10C -12C discharge i could safely go up to 50A draw.

next was the 19x10 : 45 A and 1292 W of power. now we're talking. handled the vertical stuff in the wind even ! flights were limited to 8 minutes for all props and average current put back into the cells ranged from 2000 to 2600 mah. i put in 3400 mah once but that was a 11 min flight.

today i tried a 18.5x12 prop. this is the BOMB ! my friend gave me this to try. 51 A draw and 1380 W. motor temp was 40 degrees C and the batteries were just warm. no need to let them cool down, i put them on charge as soon as i landed.

the weird thing is that the motor seemed cooler with the 18.5x12 prop and after 8 minutes i put back in 2200 mah ?! i would have thought things would be hotter.

anyways my learning continues and after 20 years of flying glow planes, i can't remember being this excited about R/C. it's a new world, new language and new technology. it's kind of expensive at the outset, but i personally can't go back to glow. just can't. this is way too simple at the field. show up with tx, batts, plane and screwdriver to screw wing and belly pan on. plug in, set idle and go fly. land and repeat.

the draw back is the number of packs needed and the wait time to recharge. also the fear of screwing things up. but with a little caution and education and common sense it' well worth it.

i fly the Advanced sequence and this current set up is very capable of flying this. probably even the Masters/Expert level. not FAI though. but this isn't the plane to do that with anyways.

some new pictures of a cardboard cooling shroud i made to funnel all incoming air over the motor and esc. hard to see in the picts but it is one modification that worked the first time out. motor is much , much , much cooler.

i'm a die hard heli guy at heart, and this venture into electrics has made be sell all my glow stuff and plunk it down on a Miniature Aircraft ION heli. i was scared about using two 4900 4S2P packs, now i'm dealing with two 8600 5S4P packs...... oh boy !!! lovin' every minute of it.

darren

Malcolm H

Darren,

Could you explain more about your cooling mod? I am running a Hacker C5013XL in an Impact (I know yours is an outrunner). I have an air dam in my belly pan which pushes the air up towards the motor where it can then flow rearwards over the cells. I also have the cheek cowl louvres opened to hopefully allow more cool air in but I have no ducting to push this air towards the motor. The setup runs reasonably cool in low ambient temps - I can keep my hand on the motor after landing, but in higher ambient it runs significantly hotter. I was thinking of adding some internal scoops to duct the air form the cheek inlets over the motor.

Thanks Malcolm

jamesjoneill

I think some scoops from the cheek openings would be sensible. Any air entering the cowl that does not go over the hot bit - be that ic or electric - will actually work to reduce the cooling effect as the air has to escape out of the outlet hole and thus will restrict the useful flow of cooling air. Redirecting this air over the motor will allow it to do useful cooling work.

Don't forget that the total outlet area needs to be at least twice the combined area of all of your inlet openings to allow for expansion of the air as it heats up.

James

Malcolm H

Good point James,

Actually my outlet area is more than 3 times the total inlet area.

This cooling business is very complex. I was reading some stuff on an Aussie C/L and F/F engine tuner's site. His contention is that high speed low pressure air is not good for heat transfer and that what is required is high pressure slow moving air. You get this by providing a plenum chamber to slow the air down which of course increases its pressure as per Bernoulli. He cites this as full size practice and gives the pylon racer Rare Bear as an example which apparently has a huge plenum in front of the radial engine.

Anyone shed any more light on this?

Malcolm

jamesjoneill

Not sure it's really going to make much difference. Ultimately the amount of energy removed by the cooling air will be dependant on how much air you have going over the engine - if you slow it down, sure you'll get higher pressure air but you will also get a lower mass flow rate over the engine which will work in the opposite direction and reduce your heat transfer. More important is increasing the convection rate which involves increasing the flow rate over the engine.

Many full size aircraft with large powerful engines (the sea fury for instance) had the opposite problem to ours - that of over cooling. They have retactable covers to restrict the flow of air so that the engine can reach optimum temperature. The are retractable so that they can be open on the ground where there is little air flow, but are closed immediately after take-off. The rare bear reno racer has a very similar layout of engine/cowling/spinner to the sea fury and I would bet that it has air flow restrictions not to increase the cooling but to decrease it.

James

funnflyerr

My Feedback: (11)

Check out this elegant cooling solution by former Japanese F3A champion Hajime Hatta.

[img][/img]

Hatta-san has electrified his proven Explorer design. Click on the link for details.

[link=http://www.little-bellanca.com/report/report/050203/]Original, in Japanese[/link]

[link=http://translate.google.com/translate?hl=en&sl=ja&u=http://www.little-bellanca.com/report/report/050203/&prev=/search%3Fq%3D%25E5%2585%25AB%25E7%2594%25B0%2Bf3a% 26hl%3Den%26lr%3D%26rls%3DGGLD,GGLD:2004-16,GGLD:en]English translation[/link]

Adamg-RCU

I saw Darren fly his Infinity this weekened. The airplane and power system made a very impressive combination, and looked very capable of flying the current Masters sequence.