E-combat Build techniques

[highflier]

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

[sheepy]

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.

[highflier]

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

[sheepy]

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.

[highflier]

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

[sheepy]

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.

[sheepy]

I just ran motocalc numbers for the 20/10/5, and it sounds perfect for ssc combat. What airframe are you currently using?

[highflier]

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

[sheepy]

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.

[sheepy]

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

[highflier]

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

[sheepy]

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

[sheepy]

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.

[highflier]

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

[sheepy]

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.

[highflier]

Your problem is definetly the motor. While it would make sense to just double the pitch and cut the rpm's in half it just does not work that way. Output is measured in Watts. If you were to exchange the motor with a 6 turn version I will promise you that you would be much happier with the way it flies. But be adviced that th flight times will shorten. I know that is going to cost you a lot of money to find out if it meets your expectation. To bad you are not closer to me. I would love to see the plane. I would have also let you try my 5 turn motor that would fly the plane with a 7" prop. You want to get the system you have up to at least 20 amps. 25-30 Static amps would be ideal.

If your battery and ESC are rated for it. Put more prop on what you got to raise the Amps. I think a 10 x 7 would show real improvement. But to be honest I do not think that you will get that motor to fly like to hope.

If I had to guess I would say the 22/10/6 would make a good try. with an 8 x 5 or 8 x 6 prop.

Highflier

[sheepy]

I agree with you. I was also considering trying 12 cells or 4s lipos to see what it would do. Will need to ubec or modify esc to handle separate rcvr pack. I will definitely try a 9 or 10 /7 just to see how it goes. Esc should handle it, and will see if I can keep amps below 17 with either combination on the lipos. Under 20 constant on nimh. The real problem is the class of combat has these real physical limits on rpm/prop. If I can't get it to work with similar static pitch speeds, then I won't be able to compete anyway. This weekend, I might actually get to see my buddys plane fly and determine that mine is just fine and his is a wallowing pig too(I doubt it). There must be something where the 8x6 doesn't generate the speed or thrust like an 8x3 turning at twice the speed. Another consideration could be that the .15 slimers are really unloading like crazy in flight(turning up to 20k). That might also be the case, my configuration isn't unloading that much. Motocalc does say it should unload to over 9500 in the air, so that would be atleast the equivalent to 8x3 at 19000. Looking at the watts, I am currently using 133 watts, whereas a TT .15 would put out almost 300 watts(.40 hp). It will be interesting to see what it would do if I can get it up to at least 200 watts.

[highflier]

A 8 x 3 prop at 15000 Rpm's is probably close to a 8 x 6 at 10000 Rpm's .

Do the rules define the pitch and the RPM's or just the Diameter and the RPM's I would think it would be the the diameter and the RPM's in which case I say stick with the 8 x 6 and add more cells as you suggested or get a hotter motor. Why the 17 AMP limit????

If it is for flight time keep in mind.
1) Once you are up to speed you can throttle back a little until you are moving in for the kill.
2) Just as props unload so do the Amp's.
3) Bigger batteries are avalible.


Highflier




Highflier

[sheepy]

Motocalc said 17 amps was the max for the 22/10/10. Megamotorsusa says 20 amps. It might be easier for me to pick up another motor. The LHS has the himaxx 2825-2300 which looks good. Static rpm is 15k at 30+ amps, but unloaded is 22k under 15 amps. This is with a MA 8x3. The rules specifically limit to MA 8x3 prop at 17500 rpm static. 24 amps at best lift to drag. How do you figure that 10k with 8x6 is equal to 15k with 8x3? The formula I always use is rpm * pitch / 1080 = speed in mph. Obviously this is not correct for my application.

[highflier]

Prop effeciency plays a role. I used motocalc to determine Watts out and change props to match watts out. I am sure that I am not right either. I just taking a guess. I can tell you for a fact the 22/10/5 flies my 2 lb plane nicely

Highflier

[sheepy]

What is strange is that motocalc says an 8x3 turning even 22k isn't even coming close to 50 mph, but they are. With the himaxx 2825-2300, I will be turning 15k static on 8x3, but unloading to 22k with 3s lipos. This will be totally within the specs of the class because it is under 17.5k. the motor is only $70 including a prop adapter. One drawback is it has a 4mm shaft instead of 5mm. I dorked the 5mm a good one, and there was no damage. I am concerned the 4mm might bend. Time will tell. I have 2 weeks to get one ready for the big combat meet in paris texas. I will primarily be flying my slimers, but it should give me a chance to try electric in real combat. It is nice to not have a slimey mess to clean up every time I go out. Also it is a snap just flying because you plug and go. I really like that. I might also try the himaxx 3630-1500 for 'b' combat which is limited to .30's or less with no other limitations. Typical to high end airframes might be flying 65-70 mph. Most turning a ma9x4 at 18500-19500 static, and unloading to 20k-21k. It would be so nice to unload the planes, and plug them in and fly. No messing with fuel etc, and no cleanup. I am sure I will find another use for the 22/10/10. It was fun flying it, just too slow. Maybe I can give it a try in one of the pica corsairs I got for scale combat. The picas used to be good, but they just explode in mid-airs. Combat construction is significantly different than it used to be.

[vanduynk]

Hey Guys I am Running the following Combo:

Wing Warrior ERaider
Mega 16/15/4C Combat motor (has 5mm shaft instead of normal 3.2mm)
cheapbatterypacks.com 2100 Nimh 8 cell
Pheonix 25 ESC
MasterAir Screw 7x4 G/F Series Prop

I clocked this plane with a radar gun at 75-80 mph out of a dive and 65 mph flat level flight. Awesome power and speed. get about 5-7 minutes on a pack mostly at full throttle.

I Also Have a Wing Warrior EZipper MKII that was clocked at 99.8 mph out of a dive and 85 mph level flight with the same setup except a 10 cell pack

I don't know if this would be legal but i just fly with a bunch of buddies in an open field anyways. and thought you might want to hear.

By the way I notice that you guys are all running Mega 22/XX/XX motors is this just for shaft size? (which is fixed with the new Combat motors) Or is this because of the rules? Also any good web sites for the 'rules'

Thanks

K

[highflier]

I used to use the 16/15/4 In combat but after the shaft broke I switched to the 22/10/5 It does not quite perform the same but it is close. I also fly the Raider in combat and can not count how many midair's I have had. I thought about ordering a 5MM shaft version of the 16/15, But don't really need another motor rihgt now.


Highflier

[sheepy]

For rules, go to http://www.rccombat.com . There are several classes. What I am shooting for with the 22/10/10 and now the himaxx 2824-2300 if the SSC class. The other class I currently fly with .25 slimers is class 'b'. Initially, I did look at the 16/15/4, but did not like it because of the sha ft. I have not heard of the 'combat' versions of the mega motors. One other I am looking at for class 'b' is the himaxx 3630-1500 running a 9x6 prop. A big thing in combat is to have a big wingspan. Its like putting bigger guns or rockets on a real plane. Wing loading is important too. 3 years ago, almost all open 'b' planes were running 36" wings, and wing loadings of 20 oz/sqft. Now the wings are usually at least 64" and several are running 72" with at least 600 sq in of area. The performance is incredible. This is with a .25 on some sort of short tuned pipe where the typical prop is ma 9x4 turning at least 18.5k static, and unloading over 20k. Dow hiload 40 or foamular 400 is the foam of choice, reinforced with fiberglass rods or polypropolene rods. Beaded foam is much lighter, but does not absorb the energy very well. These wings can take incredible hits, and sustain little damage. Do not use tubes for re-inforcement. They crush very easily. Fiberglass cloth is not very strong, because it tears easily once it is started. Kevlar was a short lived fad that died. I don't know if it was due to expense, or if it was too brittle due to the method of application. Ripstop nylon is a very effective covering applied with water based polyurethane. The key is to make sure the energy of impacts can be absorbed instead of something breaking.

[vanduynk]

The 'Combat' 16/15/XX are new I bought mine at wingwarrior.com when they first came out unfortunatly i think that me and my buddies bought them out, (they said they will have more coming in but at a higher price). havn't had any trouble with them even with the stiff props we are using. Its nice to know that you switched because of the prop size, that means i don't need a new motor to increase performance! I'll Have to read up on the 'Rules' though I don't even know if there are any sactioned events around here. would be nice to know though...I don't know about you guys but we have 4 people flying everyday at noon near my work for about an hour, we usually fly from on the hard deck to about 75' during combat and rarely have a hit that forces a landing even if does send you into a flat spin....maybe we arn't hitting that hard yet but if a 'Kill' is a hit that forces a landing, and if the 'Heats' are only 5 minutes it doesn't seem like too many people would get taken out........of course I havn't read ANY of the rules yet so don't jump my case.

P.S. These Planes are awesome, they take a liking and keep on ticking.

[vanduynk]

Here is a pic of our newest plane. This my buddy and his 5 spar Raider, Hidden Servos for less drag and less headached.....no more retrimming after a hit for him.

[vanduynk]

Close up

[vanduynk]

wow that pic sucks....oh wells more later

[sheepy]

Very little RCCA combat in the oregon area. A few years ago, there was a fair scale combat following. Montana had one of the largest scale events with several thousand $ in prizes. That has withered and died. Your best bet to see RCCA type combat is probably in northern california.