Back at AP !
Took the Easy Star out, for the first time in 5 months...
Quite cold (4 C), but sunny. I fitted the Pentax A20 with infrared shutter, not the Canon Ixus 860 (wide angle lens is nice, but its not as good optical quality as the Pentax).
Here's the outcome. A friend of mine came by, jogging with a friend of her, and I was able to grab a few shots of them.
Marc
Quite cold (4 C), but sunny. I fitted the Pentax A20 with infrared shutter, not the Canon Ixus 860 (wide angle lens is nice, but its not as good optical quality as the Pentax).
Here's the outcome. A friend of mine came by, jogging with a friend of her, and I was able to grab a few shots of them.
Marc
Easy Glider power consumption
Here's the data from a real flight: full throttle launch, where power is at the motor maximum transient value (200 W). The Easy Glider can maintain lefel flight, with easy turns, with less than 20 W of power !
Easyglider with flaps
Here are some photos of the flaps I just put on the EasyGlider. First flight was not a success: the butterfly makes the plane climb so much, that full down elevator cannot counter, so the plane climbs, stall, dives, climb, stalls, etc. Not good !
New EasyGlider setup.
I changed the power drive of my EasyGlider to the following:
Dualsky XM2830CA-10 (55g 200w kv1180 14A best, 19A max)
ESC Dualsky 30A XC3012BA
Cone 40mm ppales 45 taille 12x8, pied pale 8 axe 3, axe mot 3.2
Blades Aeronaut cam carbon 11x4
(actually I just changed the blades from 11x6 to 11x4).
Measured output:
2S 2200 mAh: 13A, 95 W.
3S 1300 mAh: 17A, 160 W.
The overall efficiency is very good in 2S, and the plane has a good climbing angle, with just 90 W of input power, amazing !
With 3S, it climbs very fast. It can be launched at half throttle (6A : 60 W).
Dualsky XM2830CA-10 (55g 200w kv1180 14A best, 19A max)
ESC Dualsky 30A XC3012BA
Cone 40mm ppales 45 taille 12x8, pied pale 8 axe 3, axe mot 3.2
Blades Aeronaut cam carbon 11x4
(actually I just changed the blades from 11x6 to 11x4).
Measured output:
2S 2200 mAh: 13A, 95 W.
3S 1300 mAh: 17A, 160 W.
The overall efficiency is very good in 2S, and the plane has a good climbing angle, with just 90 W of input power, amazing !
With 3S, it climbs very fast. It can be launched at half throttle (6A : 60 W).
Sink rates of EasyGlider
Here it is, measured with ZLog on a calm day, in neutral air.
Easy Glider is at 890g (+8g Zlog).
Easy Glider is at 890g (+8g Zlog).
Normal: -0.8 m/sClimb rate with current setup (110 W) is about 3 m/s.
5mm flaps: -1.07 m/s
5mm spoilers: -0.7 m/s
New EasyGlider setup
I changed the power drive of my EasyGlider to the following:
Dualsky XM2830CA-10 (55g 200w kv1180 14A best, 19A max)
ESC Dualsky 30A XC3012BA
Cone 40mm ppales 45 taille 12x8, pied pale 8 axe 3, axe mot 3.2
Pales cam folding prop Graupner 11x6
The measured output is very similar to what is predicted by Motocalc (with 2S Lipo):
16 A, 115 W.
Motocalc adds: thrust 630g, 5700 rpm, Pitch speed 15m/s, 78% efficiency.
The plane can maintain level flight with just 2 A (15 W), at 7.5 m/s (stall speed 5.5 m/s).
This data is very similar again with what is indicated by Dialsky Calc 3.02.
With that prop, it is not possible to use 3S Lipo, because the motor would be destroyed (21 A > 19 A), or throttle should be kept below 70% (17A, 122W, 65% eff, thrust 630g), similar to 2S at 100% throttle.
It doesn't seem possible to use another prop size, and have good values for 2S and 3S.
With this new setup, I was able to gain 120g on the plane, and thus reducing its AUW from 1010g to 890g, and improving the CG position (now spot on 70mm). It feels very light in flight. With flaps, the plane flies very very slowly, and landing is almost done at walking speed !
It seems the CG can be brought further to the rear, as a dive test indicates it is still very much forward.
Next step will be to measure climb and sink rates. Motocalc indicates: 3.4 m/s climb, and -0.6 m/s sink.
Dualsky XM2830CA-10 (55g 200w kv1180 14A best, 19A max)
ESC Dualsky 30A XC3012BA
Cone 40mm ppales 45 taille 12x8, pied pale 8 axe 3, axe mot 3.2
Pales cam folding prop Graupner 11x6
The measured output is very similar to what is predicted by Motocalc (with 2S Lipo):
16 A, 115 W.
Motocalc adds: thrust 630g, 5700 rpm, Pitch speed 15m/s, 78% efficiency.
The plane can maintain level flight with just 2 A (15 W), at 7.5 m/s (stall speed 5.5 m/s).
This data is very similar again with what is indicated by Dialsky Calc 3.02.
With that prop, it is not possible to use 3S Lipo, because the motor would be destroyed (21 A > 19 A), or throttle should be kept below 70% (17A, 122W, 65% eff, thrust 630g), similar to 2S at 100% throttle.
It doesn't seem possible to use another prop size, and have good values for 2S and 3S.
With this new setup, I was able to gain 120g on the plane, and thus reducing its AUW from 1010g to 890g, and improving the CG position (now spot on 70mm). It feels very light in flight. With flaps, the plane flies very very slowly, and landing is almost done at walking speed !
It seems the CG can be brought further to the rear, as a dive test indicates it is still very much forward.
Next step will be to measure climb and sink rates. Motocalc indicates: 3.4 m/s climb, and -0.6 m/s sink.
Easy Glider current setup
Motor: Mega ACn 16/15/5 With 1:3.3 gearbox.
(KV 1800, equivalent KV with gearbox: 550)
Prop: 15x10 Graupner folding prop.
ESC: Phoenix 35
Motor + Gearbox: 135g
ESC: 30g
Prop & spinner: 54g (spinner 42, prop holder 38, motor shaft 4)
total: 220g.
Wing with nano-s: 156g (spec is 115 + 8 (servo) + 10 (ext. cable) = 133g)
Wing bar: 54g
Fuse with receiver: 448g
Canopy: 19g.
2S 2200 Lipo: 129g
Total flying weight: 1010g.
CG is at 58mm.
With 2S 2200 Lipo, WOT is 15A, 115W, 3500 tr/min, 800g traction (all measured).
I need to lighter the plane, with 2S lipo. The stock setup has a 1220 KV motor and a 10x6 prop.
On 3S (10.5v) it will go 11.000 rpm. To have the same speed on 2S (7.5v), KV needs to be 1700.
Here's what Motocalc says:
10A, 70W, 7500 rpm, 400g traction.
With 3S: 17A, 180W, 10000rpm, 700g traction.
Motor: Dualsky XM2830CA-10; 1180rpm/V; 0.88A no-load; 0.09 Ohms.
Speed Control: Castle Creations Phoenix 35; 0.0045 Ohms; High rate. or 30A - XC3012BA DUALSKY
Drive System: Generic 9x4.5in Prop; 9x4.5 (Pconst=1.31; Tconst=0.95) direct drive.
Cone.
Stats: 77 W/kg in; 60 W/kg out; 5.7m/s stall; 7.7m/s opt @ 77% (50:00, 34°C); 8.7m/s level @ 85% (43:05, 35°C); 1.36m/s @ 10.1°; -0.63m/s @ -4.7°.
The full-throttle motor current at the best lift-to-drag ratio airspeed (7.6A) falls approximately between the motor's maximum efficiency current (8.4A) and its current at theoretical maximum output (40.7A), thus making effective use of the motor.
The static pitch speed (14m/s) is within the range of approximately 2.5 to 3 times the model's stall speed (5.7m/s), which is considered ideal for good performance.
The static thrust (400g) to weight (912g) ratio is 0.44:1, which will result in medium length take-off runs, and no difficulty taking off from grass surfaces (assuming sufficiently large wheels).
At the best lift-to-drag ratio airspeed, the excess-thrust (154g) to weight (912g) ratio is 0.17:1, which will give good climbs and acceleration. This is a good in-flight thrust to weight ratio for a basic trainer.
DualSky Calc.
9x4 CAM Folding Prop Graupner
(KV 1800, equivalent KV with gearbox: 550)
Prop: 15x10 Graupner folding prop.
ESC: Phoenix 35
Motor + Gearbox: 135g
ESC: 30g
Prop & spinner: 54g (spinner 42, prop holder 38, motor shaft 4)
total: 220g.
Wing with nano-s: 156g (spec is 115 + 8 (servo) + 10 (ext. cable) = 133g)
Wing bar: 54g
Fuse with receiver: 448g
Canopy: 19g.
2S 2200 Lipo: 129g
Total flying weight: 1010g.
CG is at 58mm.
With 2S 2200 Lipo, WOT is 15A, 115W, 3500 tr/min, 800g traction (all measured).
I need to lighter the plane, with 2S lipo. The stock setup has a 1220 KV motor and a 10x6 prop.
On 3S (10.5v) it will go 11.000 rpm. To have the same speed on 2S (7.5v), KV needs to be 1700.
Here's what Motocalc says:
10A, 70W, 7500 rpm, 400g traction.
With 3S: 17A, 180W, 10000rpm, 700g traction.
Motor: Dualsky XM2830CA-10; 1180rpm/V; 0.88A no-load; 0.09 Ohms.
Speed Control: Castle Creations Phoenix 35; 0.0045 Ohms; High rate. or 30A - XC3012BA DUALSKY
Drive System: Generic 9x4.5in Prop; 9x4.5 (Pconst=1.31; Tconst=0.95) direct drive.
Cone.
Stats: 77 W/kg in; 60 W/kg out; 5.7m/s stall; 7.7m/s opt @ 77% (50:00, 34°C); 8.7m/s level @ 85% (43:05, 35°C); 1.36m/s @ 10.1°; -0.63m/s @ -4.7°.
The full-throttle motor current at the best lift-to-drag ratio airspeed (7.6A) falls approximately between the motor's maximum efficiency current (8.4A) and its current at theoretical maximum output (40.7A), thus making effective use of the motor.
The static pitch speed (14m/s) is within the range of approximately 2.5 to 3 times the model's stall speed (5.7m/s), which is considered ideal for good performance.
The static thrust (400g) to weight (912g) ratio is 0.44:1, which will result in medium length take-off runs, and no difficulty taking off from grass surfaces (assuming sufficiently large wheels).
At the best lift-to-drag ratio airspeed, the excess-thrust (154g) to weight (912g) ratio is 0.17:1, which will give good climbs and acceleration. This is a good in-flight thrust to weight ratio for a basic trainer.
DualSky Calc.
9x4 CAM Folding Prop Graupner
2S: 7.5A, 54W, 7000 rpm, 344g.8x6 CAM Folding Prop Graupner
3S: 9A, 100W, 10000 rpm, 700g
2S: 6A, 44W, 7050 rpm, 336g.9x6 CAM Folding Prop Graupner
3S: 7A, 80W, 10000 rpm, 680g
2S: 6A, 44W, 6700 rpm, 449g.Aeronaut CAM carbon 9x5
3S: 7.3A (max 18A), 80W (max 190), 9300 rpm, 862g.
2S: 6A, 44W, 6850 rpm, 442gGraupner Cam 11x6
3S: 7.3A (max 16), 80W, 9600 rpm, 871g
2S: 79% 6A, 45W. Max: 71% (13A, 95W, 580g)
3S: 82% 7A, 80W. Max: 66% (23A, 250W, 1050g)
Merlin sink rates
Another set of measurements of the Merlin sink rate, done in neutral air, at 275g.
No flaps: -0.9 m/s
5mm flaps: -1.1 m/s
10 mm flaps: -1.3 m/s
Inverted: -4 m/s
The inverted sink rate with no motor is difficult to measure, as the Merlin in not stable inverted, and tries to turn upside right.
No flaps: -0.9 m/s
5mm flaps: -1.1 m/s
10 mm flaps: -1.3 m/s
Inverted: -4 m/s
The inverted sink rate with no motor is difficult to measure, as the Merlin in not stable inverted, and tries to turn upside right.
Measurements with folding prop
I did some sink rate measurements with the Merlin, fitted with a folding prop: it's the stock prop setup from the Easy Glider, that has been sitting in the drawers for 3 years ! It fits perfectly on the motor with a prop saver ! The prop size is 9.5x5. It takes the same amps from the motor as the 8x4.3: 7.5A.
Now, the sink rates are:
with flaps: -1.0 m/s
without flaps: -0.9 m/s
Interesting to see that it floats better without flaps !
The climb rate is impressing: 5 m/s !
Now, the sink rates are:
with flaps: -1.0 m/s
without flaps: -0.9 m/s
Interesting to see that it floats better without flaps !
The climb rate is impressing: 5 m/s !
Multiplex Merlin
Here's one video with the Merlin
I did some climb and sink measurements, with and without flaps or spoilerons.
Flaps are ailerons down for 4 mm. Spoilers are ailerons up for 4 mm.
No flaps: climb 3.9 m/s, sink -1.4 m/s
Flaps : climb 3.7 m/s, sink -1.1 m/s
Spoilers: sink -1.4 m/s
So flaps really make a difference for thermal (and probably slope) flying.
The plane is perfectly visible at 230m, and can probably be flown up to 300m (preferably under clouds for better visibility).
Here were some measurements I did with my other planes:
- Easy Glider: -0.8 m/s (-0.6 with flaps)
- Easy Star: -0.8 m/s
- Toro 900 @ 270g : -0.6 m/s
So the Merlin is not the best floater around, but it's very convenient: it fits in its box !
| Multiplex Merlin (video by Emilie) (6 min 24 sec) |
I did some climb and sink measurements, with and without flaps or spoilerons.
Flaps are ailerons down for 4 mm. Spoilers are ailerons up for 4 mm.
No flaps: climb 3.9 m/s, sink -1.4 m/s
Flaps : climb 3.7 m/s, sink -1.1 m/s
Spoilers: sink -1.4 m/s
So flaps really make a difference for thermal (and probably slope) flying.
The plane is perfectly visible at 230m, and can probably be flown up to 300m (preferably under clouds for better visibility).
Here were some measurements I did with my other planes:
- Easy Glider: -0.8 m/s (-0.6 with flaps)
- Easy Star: -0.8 m/s
- Toro 900 @ 270g : -0.6 m/s
So the Merlin is not the best floater around, but it's very convenient: it fits in its box !
Fixed trex by changing pinion gears !
I had crashed my two trex 450 3 times in a few weeks :mad:
I fixed them, and this gave me the opportunity to try a new thing: instead of replacing a whole HS-56HB servo, replace just the gear, for 10% of the price ! It was very easy to do (a few minutes), and the result is perfect. The servo is like brand new !
For lubrication, I used silicon spray, I hope this will work OK in the long run.
Marc
I fixed them, and this gave me the opportunity to try a new thing: instead of replacing a whole HS-56HB servo, replace just the gear, for 10% of the price ! It was very easy to do (a few minutes), and the result is perfect. The servo is like brand new !
For lubrication, I used silicon spray, I hope this will work OK in the long run.
Marc
eLogger
Typical eLogger results from stationary flight with Trex 450.
Average current is 11.6A.
Pack temperature rises steadily from 25 degrees (outside temperature) to 40 degrees (C).
mAh reported by eLogger (1289) very close to what was actually put back into pack (1284).
Average current is 11.6A.
Pack temperature rises steadily from 25 degrees (outside temperature) to 40 degrees (C).
mAh reported by eLogger (1289) very close to what was actually put back into pack (1284).
Crashed TRex 450 today...
In nose-in hover, with some wind, heli started to be too close to me (<2m), and I think some wind gust pushed it even closer. I pushed it back in reflex, and I think I messed up while it was tail-low. Next thing I now it broke in the ground. Not too much damage though: cyclic servos are dead (all 3), ball link between servo and tail rotor is broken, vertical stab broken, and main rotor shaft bent...
Main blades are intact (well, they were beaten *before* !), as well as gyro. Good !
Main blades are intact (well, they were beaten *before* !), as well as gyro. Good !
AP of friend's shop
Here are some pics taken today of a friend's shop in Vaulnaveys.
It's the first time I try to do some actual shooting with the TRex. It's totally different than using the EasyStar !
It's the first time I try to do some actual shooting with the TRex. It's totally different than using the EasyStar !
Downtown Grenoble
Taken this morning between 7:08 and 7:25. Temperature 20C, sun altitude 9-12 degrees (sunrise 6:04).
Thermals at home !
Did a quick flight today, it was hot (30 degres at 1pm), so I figured there could be some thermals.
I used my good old EasyStar (4 years old, and numerous crashes), all stock.
There was indeed some thermals ! See the graph, only 2 motor climbs (first one, and right before last).
Thermals were very stong: the plane went up +0.7m/s !
On the last run I was not able to find any thermal, and the sink rate was nominal for this plane (-0.8m/s).
This means the effective thermal climb rate was 0.7+0.8 = +1.5m/s !
Interesting to see that the stock motor and stock prop, on 2S Lipo, can propel the plane at 2.2 m/s. This is quite fast.
Marc
I used my good old EasyStar (4 years old, and numerous crashes), all stock.
There was indeed some thermals ! See the graph, only 2 motor climbs (first one, and right before last).
Thermals were very stong: the plane went up +0.7m/s !
On the last run I was not able to find any thermal, and the sink rate was nominal for this plane (-0.8m/s).
This means the effective thermal climb rate was 0.7+0.8 = +1.5m/s !
Interesting to see that the stock motor and stock prop, on 2S Lipo, can propel the plane at 2.2 m/s. This is quite fast.
Marc
Corn field (2)
July 9th 2009.
Club Guynemer annual Heli symposium
Happened this weekend in Vizille, France.
Marc
Marc
Grand Place, Carrefour, Echirolles
Taken today
Ile d'Amour
Gypsy camp, Athanor and Carrefour.
