jrotor

My Feedback: (5)

Hi,

I'm thinking about converting Kyosho Spree 380 to glow powered.
Reason ? More power and cost less(no need for expensive Li-poly battery, charger, brushless motor, esc, etc).

My question is,
Would electric plane has body frame that will overcome glow engine's power and vibration ?
Estimate on engine size ?
Any comment / advice / idea would be appreciated !
Thanks.

Greg Covey

Although it is an interesting concept, I think you'll find very fast that electric power rules under a .40-size plane.

The advantages of glow cost and power are lost in the 39" span [link=http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXDUE7&P=7]Kyosho Spree[/link] plane.

A Speed 380 (aka Speed 400) motor would be comparable to a .09-size glow engine. The Speed 400 motor is about $8, the .09 [link=http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXB443&P=7]Cox Tee Dee[/link] is $67 without any throttle control.

The light build firewall would have to be strengthened to withstand the additional vibration from the glow engine.

gwright

I would concur with Greg,.. you're going to lose performance, not gain it, by going glow on a smaller plane ,.. actually anything up to about 140~160 size i get FAR HIGHER performance electric than glow,.. but it does cost more(a lot more on the large stuff). When going really small, say 40 glow size or smaller, the performance difference is even higher. One good example is the Banchee. the "Banchee-G3D" (glow version) turns out a pound or more higher in weight than the Banchee-E3D (electric version), and of course the 46 glow has quite a bit less performance than a 500~600 watt electric setup spinning a 15 to 18 inch prop.

Matt Kirsch

My Feedback: (21)

What is the specific issue you're having with your Spree, if I might ask?

Many issues are very easy and inexpensive to resolve with electrics. You just have to know what to look for, and what to do. It's no different with a glow engine; if the engine's not running right, you don't throw it away and denounce glow power! No, you tune the engine, change the prop, change the fuel, change the glow plug, replumb the system... For someone new to glow power, these troubleshooting and tuning processes are just as mysterious and strange as the troubleshooting and tuning processes for electrics are to those of you who have flown glow.

It's a learning process, and you can't expect to know it all at once.

So, let's first try and work through your problems. Maybe you can be the electric guru at the flying field, and spread the knowledge.

jrotor

My Feedback: (5)

Matt Kirsch,
Thanks for the reply.
I'm trying to make Spree faster and fly longer without costly upgrades like brushless motor, esc, li-poly battery and charger(These are about $250 already).

Greg Covey,
Thanks for the reply.
I'm thinking about using AP engine which is around $40 with throttle control and muffler. Not $67.

BTW, u mean 0.09 engine is less powerful than 400 motor ? That's hard to believe !

Henke Torphammar

?? faster? get another plane if you want to fly fast.

most of all the 400 runns... the 0.049´s doesn´t

Matt Kirsch

My Feedback: (21)

jrotor,

What's it got in it now for a battery? Probably a 7-cell, 600mAh NiCd, right?

Upgrade to an 8-cell pack of CPB1150 cells from cheapbatterypacks.com. Total cost of about $20, with shipping. You'll do a little better than double your flight time, and increase your top end power by (8/7)^2, or about 30%. Total increase in weight is less than an ounce.

jrotor

My Feedback: (5)

So, with 8-cell pack of CPB1150 cells, how long should it fly ?

BuzzBomber

My Feedback: (4)

jrotor, I'm going to play devil's advocate to the good electric advice you're getting here. I fly both glow and electric, and for me, speed 400/480 is my practical cutoff. Above that, I've found that batteries, motors, and ESCs get too expensive......so I stick with IC engines in .15 and up range. But, I also have a TD .020 powered ship that was originally electric powered and lost over an ounce going from E power to G power--nearly anything can be powered by EITHER glow or electric if you plan carefully. If you're set on coverting the spree, I would recommend only one engine--the norvel .074. It's very reliable, fully throttleable, and weighs just about as much as a speed 400 motor. You can use a 400maH 1/2AAA Rx battery and a 6 gram throttle servo, thus potentially losing a fair bit of weight. If this sort of thing interests you, I suggest you do some research in the 1/2a forum--very friendly and innovative bunch of guys.

HOWEVER, since you've already got all the kit for electric power, I would suggest you follow Matt K.'s advice on the CBP 8 cells packs. Most of the 2/3A nimh cells are GREAT for speed 400 power, and provide a far better 'sport flying' value than spendy LiPos, in my humble opinion. I do use Lipos and brushless motors, but I think they're a bit of a luxury, rather than a necessity in most cases. Then again, I've seen Gary fly at NEAT and I know darn well he NEEDS the power to weight advantage these luxuries supply.

gwright

Actually Matt,.. that's not totally true. Here's a litte video of one of my first "larger" electric planes.

http://www.squid-ink.com/rc-photos/video/gwright2.zip

That's 64 inch span, over 1000 square inches, 4 lbs, and it's flying on a $20 endoplasma motor and 10 old-fashioned roundcells,.. panasonic 3000 nimh to be exact. Average flight time was 8 minutes. With current lipoly technology, it would have been 3.5 lbs (just changing the battery) with double the duration.

StephenT

Gary


I fly my 5.5 lb Avistar on a similar Endoplasma system. I use 8 GP3300's. 8 minutes horsing around. Longer just cruising. The biggest cost was the Griffen 55 speed controller.
Battery $50
Speed Control $75
Plane Free
Motor $25
Gearbox $13
prop $3.75
Had the radio already