rhodenga500 Show full post »
solentlife
Its not unknown for a model to be too much for power possibilities .... there's good reason particularly when it comes to Electric Flight to "Build it Light" ... 

I've been building and flying models for over 55yrs and I have to admit - I have designed / built some that my requirements proved not possible to complete.

One fact that is apparent when heavier models ... take the Polaris XL as example - the motor used is usually a lower KV to get the thrust up by using larger props. Maybe that's the case here ... look at it with a different idea on motor / prop combo ... and with reducing KV - you could likely still stay with the 4S.

Larger models or heavier models do not necessarily follow the same high KV route as smaller / lighter versions.
I'll fly anything if I can launch it ! Youtube : solentlifeuk
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Wildthing
1770g on 4s 

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Sidewayskiwi
solentlife wrote:
I'm surprised you say the 2826 is weak compared to the smaller '2306' ..... also that the 2826 will run 4S on 5" without burning out.

Emax motors - I have to say have never been strong motors when I've used them. I have several and all of them have shown I need to stay well under their max spec ratings. It would appear that may not have changed. They are also not cheap compared to other brands.

Given the weight vs size - I would suggest looking for a better motor in a slightly larger size ... have a look through RC Timer ..... Banggood ..... for example. RC Timer are a very good site to scroll through ad the data they give on their motors is in my experience fair and honest.

Dont know about 5s but ran 2826 2200kv on 4S and 6x4 prop for a couple of years now 
No issues at all
I have run and still are running 2826 on 7x5 prop on 3S bearings wear and get noisy just replace them every year 
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rhodenga500
The Turnigy 2826 2200kv motors are good and I used them for years in my hand throwers, especially the V4 jets. But they could not produce 60 ounces of thrust. I enlarged my F-18_V4 to a 36 inch wingspan and installed the Turnigy 2826 2200kv motor. Eventually, the motor burned up from too much weight. I purchased a Cobra C2814/10_1700kv motor (7x4E prop with a 4S battery which produced 60 ounces of thrust) and the 36 inch wingspan jet performed very good.

So now I have purchased two Brotherhobby Avenger 2806.5_1300KV and will test fly them with the F-15_38"WS soon on a 4S battery. The specifications are impressive (6S Battery_7X5 prop produces 88 ounces of thrust).
There is also a Brotherhobby Avenger 2812_V2_1500KV and the specifications are more impressive (8X4 prop_6S battery_80 amp ESC produced  107 ounces of thrust).
https://www.brotherhobbystore.com/avenger-2812-v2-motorcw-p0089-p0089.html
Click on the "Tech Spec Tab" to get the specs.

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rhodenga500
In reading some responses again, someone might say "Why not use 7X4 props and larger motors like the Cobra C2814/10_1700kv". The problem with the 7X4 props I do not have the clearance (they will touch the ground on take off) and the cobra motors (102 grams) are too heavy for my rear mounted motors. I would have to add dead weight to the fuselage to maintain COG with heavier motors which is non-value added to the aircraft. 
The drone motors are very light 30-45 grams and powerful which make a big difference when mounted on the rear of the aircraft and using thrust vectoring. I ordered two Brother Avenger 2806.5 _1300kv with 41 grams of weight with lots of thrust and will be testing it with a 6X4 prop wich is my maximum size for the aircraft.

When building large jets (36' WS and above)  with depron and dollar tree foam, I always consider weight, however, any hard landings with retracts and rough handling will always break something. So I continue to reinforce needed areas to solve these problems. My F-15_38"WS weight went from 65 ounces to 88 ounces to correct these issues. I build my large jets with removable wings and fuselage so I can continue to repair after crashes (with very little cost) but this also added more weight. This F-15 (38"WS) have survived three crashes (lots of damage) and many major repairs and still flying. My wife accidentally run over half of the jet in the garage with her car and I had to replace a wing, fuselage, and most of my top air foils on the mainframe.
 
I stop using cheap servos, control rods, etc., which have caused many failures in large my aircraft's. Jets this size cost about $500 plus, but thanks to RC Powers (for help and expert advice) I am able to build large size for half the cost.

This is a hobby, let you imagination be the limit.
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rhodenga500
Received and installed  two Brother Avenger 2806.5 _1300kv motors with 6X4X3 props.

Ready for flight testing.
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Wildthing
rhodenga500 wrote:
Received and installed  two Brother Avenger 2806.5 _1300kv motors with 6X4X3 props.

Ready for flight testing.


On  4S ?
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solentlife
Wildthing wrote:


On  4S ?


Taking Banggood power table as listed .... 1300kv and 4S is going to be a bit low on power compared to what OP wants ?? The table shows 6S based levels .... 

Interested to read results ...............
I'll fly anything if I can launch it ! Youtube : solentlifeuk
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rhodenga500
Test flight Data:

Used Admiral 4S_5000_40C Battery (6X4X3 props) for the first two flights. Barely could get airborne (WOT) on a grassy runway and aircraft nearly stalled on take off (too much pitch) due to not enough thrust (achieved maybe 50 ounces of thrust per motor). Had to fly WOT constantly 90 percent of time to stay airborne. Both flights were 5 minute flights with approx. 54 percent of battery power left. Landed and hand touch to checked the motor temperature (both times) and motors barely warm (almost could not tell they had been used). 

I have two 6S batteries (turnigy 3000_30C) that I will use to conduct another test flight. The 6S_3000 battery weigh less than my 4s_5000 battery, so I need to reorganize the fuselage to move the 6S battery forward to acheive the correct COG.
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solentlife
Sorry to say this - but no surprise at all .... 

In fact - I'm surprised you actually got of the ground.

I do not mean to be rude - but it appears that all the comments I and others have given has been put aside .... 
I'll fly anything if I can launch it ! Youtube : solentlifeuk
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rhodenga500
[QUOTE username=solentlife userid=6600503 postid=1309584823]Sorry to say this - but no surprise at all .... 

In fact - I'm surprised you actually got of the ground.

I do not mean to be rude - but it appears that all the comments I and others have given has been put aside ....

Solentlife,

You and Wildthing have given me good comments. I considered and evaluated all comments. Reading through all responses I considered each one as folllows:

1. Suggested Lower KV will allow a larger prop. Answer_The largest prop I can use is 6 inches. 7 inch props will hit each other.
2. Conduct a ground test to check temperature. Answer_I did this with the Brotherhobby motors before flight on 4S.
3. Motor too small and check prop angle for hitting deck. Answer_5 and 6 inch prop will hit the deck on this jet regardless. that is why I take off at the lowest pitch (upward) possible to prevent this. Once clearing the deck/ground I go vertical.
4. Look for a better motor in a slightly larger size.  Answer_purchased two Brotherhobby 2806.5_1300KV motors.
5. Suggested Racerstar 2507 series motor. Answer_Performance data (Banggood) for 5X4X3 prop showed 1400 grams (49.5 ounces) of thrust. My minimum thrust is 1700 grams (60 ounces per motor) which was built into my specs for good performance.
6. Suggested building jets light. Answer_Had to constant reinforce weak areas of this plane which added weight. The jet is not over weight, MotionRc.com have a F-35 Lighting II, 6S, 32' WS, and flying weight 2600 grams (92 ounces); F-15, 38"WS, flying weight 3080 grams or 108.6 ounces.  I normally build my large jets (fully loaded) within manufactured model specifications.
7. Loved this last suggection_That larger/heavier models do not follow the same high KV as smaller/lighter versions. Answer_purchased two Brotherhobby 2806.5_1700KV (6X4X3 props) motors and I believe this will be my choice motor for this model. Light weight and plenty of thrust. This jet can accommodate the 6S batteries and still be within manufactured model specs.

I hope that I am not being rude, I loved every response.
Thanks.
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Wildthing
rhodenga500 wrote:
Sorry to say this - but no surprise at all .... 

In fact - I'm surprised you actually got of the ground.

I do not mean to be rude - but it appears that all the comments I and others have given has been put aside ....

Solentlife,

You and Wildthing have given me good comments. I considered and evaluated all comments. Reading through all responses I considered each one as folllows:

1. Suggested Lower KV will allow a larger prop. Answer_The largest prop I can use is 6 inches. 7 inch props will hit each other.
2. Conduct a ground test to check temperature. Answer_I did this with the Brotherhobby motors before flight on 4S.
3. Motor too small and check prop angle for hitting deck. Answer_5 and 6 inch prop will hit the deck on this jet regardless. that is why I take off at the lowest pitch (upward) possible to prevent this. Once clearing the deck/ground I go vertical.
4. Look for a better motor in a slightly larger size.  Answer_purchased two Brotherhobby 2806.5_1300KV motors.
5. Suggested Racerstar 2507 series motor. Answer_Performance data (Banggood) for 5X4X3 prop showed 1400 grams (49.5 ounces) of thrust. My minimum thrust is 1700 grams (60 ounces per motor) which was built into my specs for good performance.
6. Suggested building jets light. Answer_Had to constant reinforce weak areas of this plane which added weight. The jet is not over weight, MotionRc.com have a F-35 Lighting II, 6S, 32' WS, and flying weight 2600 grams (92 ounces); F-15, 38"WS, flying weight 3080 grams or 108.6 ounces.  I normally build my large jets (fully loaded) within manufactured model specifications.
7. Loved this last suggection_That larger/heavier models do not follow the same high KV as smaller/lighter versions. Answer_purchased two Brotherhobby 2806.5_1700KV (6X4X3 props) motors and I believe this will be my choice motor for this model. Light weight and plenty of thrust. This jet can accommodate the 6S batteries and still be within manufactured model specs.

I hope that I am not being rude, I loved every response.
Thanks.


Plug in those 6S batteries and do a vertical thrust test, worry about the COG after test. If it just flies on 4S,  6S should do it, that is as long as the motors hold up. 
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jimbosflyin
Wildthing wrote:


Plug in those 6S batteries and do a vertical thrust test, worry about the COG after test. If it just flies on 4S,  6S should do it, that is as long as the motors hold up. 
I think I missed what size ESC he is useing,and can it handle a 6s with out burning up.
Parkflyers International 
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rhodenga500
Wildthing and Jimboflyin,

I have already conducted a vertical thrust test and never got to half throttle. Could not hold it.

I am using dual 80 amp ESC's. Actually the brotherhobby avenger 2806.5_1300kv use less current that the smaller 2306 series motors. I am very impressed with the specs (6S battery, 50 amp esc, 47.59 grams weight, 7" prop, and 2529 grams (89 oz.) of thrust. See attached documents from http://www.brotherhobbystore website.

I have ordered two Brotherhobby 2806.5_1700KV, for 6X4X3 props,  which is even a better match for my 38 inch wing span jets than the 1300KV motor. 
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Wildthing
rhodenga500 wrote:
Wildthing and Jimboflyin,

I have already conducted a vertical thrust test and never got to half throttle. Could not hold it.

I am using dual 80 amp ESC's. Actually the brotherhobby avenger 2806.5_1300kv use less current that the smaller 2306 series motors. I am very impressed with the specs (6S battery, 50 amp esc, 47.59 grams weight, 7" prop, and 2529 grams (89 oz.) of thrust. See attached documents from http://www.brotherhobbystore website.

I have ordered two Brotherhobby 2806.5_1700KV, for 6X4X3 props,  which is even a better match for my 38 inch wing span jets than the 1300KV motor. 


Sounds like it should rip the skies up 🙂 
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