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Old Jan 21, 2004, 05:15 PM
Speed cost money.
highflier's Avatar
United States, FL, Marathon
Joined Dec 2002
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E-combat Build techniques

Hi,

I don't fly in approved E-combat events. But I do fly agaist a couple of friends. We losely use the scoring rules of Contact, with a crash while the other plane does a loop or role to score 1 point. Other then that we threw out the rulebook. I our quest to defeat others by durability and power in the sky. Of course we want to do it at an affordable cost. Here are a few things we did.

1) Only use all EPP planes. EPS does not hold up to over powered E-combat. Ulitmate spar Raider is what we are currently working on. I am sure there is other good choices also.

2) Keep the battery in the plane. Use corplast on the underside and use Velcro or better yet plastic Clamp type tie downs to go through the wing and coroplast to hold it in tight.

3) 3.2 MM moter shafts were bending. Thus we changed to a motor that has 5MM shaft. We have not had a single failure with motors since we changed to the Mega 22/10/5. We tried AXI but the outrunner's don't take kindly to sudden impacts.

4) Props are a common break point. To date we just use the cheap ones MA 7 x 4's

5) You need lots of AMPS so we take FAUP in 8 cell flat packs and double rap them in straping tape. Add heatshrink on top of that. This prevents the battery welds from breaking in the really nasty collisions.

I post a few more if I get any interest in this thread.

I would like to see what ideas others have used.
Also if anybody is just North of Philly and wants to join in someday just send me a PM


Highflier

Fly Fast... Hit Hard... Fly away laughing
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Old Jan 22, 2004, 06:11 AM
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sheepy's Avatar
Smithville, MO
Joined May 2003
147 Posts
I am interested in any info you have on setting up e-combat ships. I have flown combat similar to what you do except it was slope combat, so loops or rolls were very difficult to accomplish after knocking someone down. I am using a Zagi 3? epp/eps plane with carbon tube spars. Very tough. I have been thinking of enlarging a wing and using a mega 22/30/3 on 12 cells w/ 9x7 prop. That should be competative even with .25 size slimers.
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Old Jan 22, 2004, 10:18 AM
Speed cost money.
highflier's Avatar
United States, FL, Marathon
Joined Dec 2002
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How fast do you need this plane to fly?

I would think that the 22/20/XX would be more then enough HP to compete. With the 22/10/5 and 8 cells I don't get pure vertical but I do get great climb and probably about 50 MPH in the straights. I would slow to about 30 MPH when I am make hard aggressive turns one after another.

Motocalc says with Mega 22/20/3 with 10 FAUP 62% throttle = 44MPH for 10.5 minutes, TOP END 100% THROTTLE HIT SPEEDS of 60+ mph that is with the Zagi airframe. I would guess you would do a lot better with a Raider. It's airfoil definitely is better at higher speeds. Oh I was using a 7 x 5 prop. I like the smaller props in combast because I feel they do not break as much as the larger props do with contact.


My thoughts are that you should stay with the 22/20/XX motors. You do not want a gear drive in combat and there is not much of a chance you keeping the AMP's down with 12 Cells. The planes will loose some manuverablity if you use Sub c cells. If I was to try it agaist slimers. I think I would use
10 FAUP
7 x 5 prop
22/20/3

I figure since I would be staying below 40 AMP I could get away with those cells. If I needed more power I would stick with the motor (It's rated to 70 AMP) and I would reprop and use 3300 cells X 10

Highflier
PS.
One last thought the 22/30/XX is a .40 slimer class motor
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Old Jan 22, 2004, 10:44 AM
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Smithville, MO
Joined May 2003
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In slimer .25 combat, the typical setup is spinning a MA9x4 prop from 18k to 20k, which probably gives a pitch speed of 75mph. I would bet the realistic speed is more like 60-65, but have not radared one. I would be opting for a foamular 250 or 400 foam wing with 1/8 fiberglass rod spars and leading edge. This type of wing construction is light, and super strong. Its hard to find the right motor to go with this, because motocalc does not choose motor/battery combos that fit the typical combat requirements. I was thinking of the 22/30/3 because flyingmodels.org had some test data which indicated it would be a good candidate. I was also thinking of the gp3300 bats, and motocalc said these would not handle the current requirement, but 3300's would be the smallest to get the 5 minute flight time. Lipos are out of the question, because I fly around dry grass fields, and am concerned about fire hazards if the lipos were damaged in a mid-air. I have also thought about the orbit10-25, and the axi 2820/10. I am still in the dream stage on this, but hope to have something to test in a few months. The only other alternative would be 'class a' combat which limits engines to .15's, and making a suitable choice to replace the power of a .15(spinning 7x4 at 18k). I already have a zgator 280 plane which might work for a class 'a' plane.
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Old Jan 22, 2004, 08:54 PM
Speed cost money.
highflier's Avatar
United States, FL, Marathon
Joined Dec 2002
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Don't use the AXI. We have tried it and in the first few collisions the motor will be toast. I think it is the magnets getting thrown. Certianly wish I could see your final results. I could use a few new tricks to throw at my friends. Ok maybe I will moto calc a few other ideas now that I know you need 5 minutes of flight time.

Highflier
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Old Jan 23, 2004, 10:11 AM
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Smithville, MO
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I have had another thought about the RCCA SSC(slow survivable combat) which allows .15's turning MA 8x3 props at no more than 17.5k. I am checking into the possibility of using an 8x6 turning no more than 8750 rpm. This would allow the use of a 16/15/8 on 8 cells, and get the current down to 13 amps. This would be on an airframe with AUW of 40 oz(the minimum weight allowed) and in the 50 mph range. The SSC class of combat is still a provisional event, and currently no electrics are allowed. This might be an opportunity to test electrics in combat. There is a big event in paris texas in march. I might be able to test one there if they allow it. what prop are you using on your 22/10/5? It looks like the 22/10 series could work for me too.
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Old Jan 23, 2004, 06:05 PM
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Smithville, MO
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I just ran motocalc numbers for the 20/10/5, and it sounds perfect for ssc combat. What airframe are you currently using?
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Old Jan 24, 2004, 06:04 AM
Speed cost money.
highflier's Avatar
United States, FL, Marathon
Joined Dec 2002
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I am flying a wing warriors Raider with 8 FAUP's on a 7 x 5 MA prop. I think the 22/10/6 would be the motor for the 8" props

I would stay away from the 16/15 motors in combat. Then run good until you have a good hit then the shaft get bent.

I have a site with a few videos at
www.jstelzer.com
Link to Rc planes made easy

Highflier
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Old Feb 13, 2004, 05:09 PM
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Smithville, MO
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Well, I have a mega 22/10/10 in my grubby little hands, and some cbp1400's from cheapbatterypacks.com, and tanic 1700 as well. It runs great static. the nimh's are better than the tanics, and I will probably need the weight anyway. They will be installed in a teamseaholm.com avenver 972s. I also have the kit in my grubby hands. It will probably be a week before it is ready for test flights.
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Old Feb 28, 2004, 06:21 PM
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Smithville, MO
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Its finally built, and ready for its maiden. The kit is an Avenger 972s available from teamseaholm.com. Mega 22/10/10, phoenix 35, tanic 1700 lipos, estimated AUW is 2 lbs 10 oz, will weigh it monday.http://www.sheepzilla.com/images/evenger1.jpg
http://www.sheepzilla.com/images/evenger2.jpg
http://www.sheepzilla.com/images/evenger6.jpg
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Old Feb 29, 2004, 07:05 AM
Speed cost money.
highflier's Avatar
United States, FL, Marathon
Joined Dec 2002
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Let me know how it goes.

I like the looks of the plane. My only consern is the wind that you selected. I think that a lower wind I.E. a 22/10/5 or 22/10/6 would run better.

Oh No one other thing. Don't use the Tanics during combat. A hit on them could really make for an explosive flight

Highflier
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Old Feb 29, 2004, 03:02 PM
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Smithville, MO
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The test was a success(no crashes), but the conditions were horrible. sustained 26mph winds with gusts to 35. The plane was always wanting to weathervane into the wind, and forward speed into the wind was not good. Launch was a non-event, but it was very difficult to gain any ground against the wind, once you tried to go straight, it would still weathervane. It was a little pitch sensitive, but I want to try again in less wind. Maybe I can get out to fly this week in more normal conditions. I did not try the nimh's because conditions were so bad.Initial tach reading on 1700 tanics was 8900 rpm with ma 8x6. http://www.sheepzilla.com/images/evenger7.jpg
Weights for the Evenger:
total flying weight with tanic 1700's, 2 lb 10.4 oz
total flying weight with cbp1400 nimh's, 2 lb 15.2 oz
wing only with 555 rcvr and hs322 servo, 21.6 oz
fuse with without bats, 13.6 oz
nimh pack weight, 9.6 oz
tanic lipo pack weight 4.8 oz
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Old Mar 03, 2004, 06:56 AM
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Smithville, MO
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The wind has subsided, and I had a chance to give the electric SSC another try today. Initial tach on the ground with a ma 8x6, was 9200 rpm. That should be the equivalent to an 8x3 turning 18400 static. First launch I gave it a fair chuck, but it eventually nosed in. Not enough power. No damage, so I made another attempt. I gave it a heavy toss, and it was better, but was still a wallowing pig and never attained enough speed to make it stable. No damage. third try, I gave it a huge toss, and it was airborn. It was barely controllable and I was able to slowly get it up to altitude. Once in the air and up to speed, it was like flying a very slow trainer. After about a minute into the flight, I got enough of a feel, and enough altitude to try a loop. It made it, but just barely. It did flop on the top. Later attempting rolls was just as bad. It would lazily roll, but by the time it was 1/2 way through, it would be diving straight toward the ground. No wonder it couldn't gain much ground against a 26mph wind this weekend. It appeared the top speed wasn't much over 30mph today flying straight and level. That is close to what motocalc actually predicted turning around 9000 rpm. The pitch speed might be 55mph, but the true airspeed was probably 35-40. It was flyable, but performance was way down. I flew for about 7 minutes and landed before the LVC kicked in. Performance after 7 minututes wasn't much worse than initial performance. Either way it was a dog. Motocalc showed a 200rpm difference between static and flying rpm. I would say that was about right. I wonder if the .15's are unloading 1500 or more RPM to actually get to 50 mph after airframe drag.
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Old Mar 03, 2004, 08:14 PM
Speed cost money.
highflier's Avatar
United States, FL, Marathon
Joined Dec 2002
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Sheepy,

Can you confirm the motor you are trying? I would recommend a lower turn motor. My wings are over 2 LBS and they will fly at about 1/2 throttle with a 9 cell pack.

How many amps are you pulling?

My 22/10/5 , 9 cell pack , 7 x 4 prop pull about 22 amps static

Highflier
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Old Mar 04, 2004, 06:06 AM
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Smithville, MO
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It has a sticker on it that says 22/10/10, and the static figures are very close to what motocalc predicts. I have been waiting on a whatt-meter for over 6 weeks. I still think motocalc is close on predicting 12 amps at 11 volts. What is strange is that a buddy of mine has the same airframe, that weighs 1 ounce more than mine, and is turning a ma8x3 at 17600, with a TT .15 slimer. It supposedly flies great. I would think that if I am turning a ma8x6 at 9200 that I should actually be flying faster than my friends plane. The weather might be good this weekend, and maybe 'good' flight in his opinion is different than good for me.
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