08-01-2012, 04:39 PM
Date: 08 Jan 12
Conditions: Zero wind, overcast but good visibility, moderate strip condition
Aircraft: Durafly T-28B Trojan (1100 mm wingspan, 910 mm length)
Can we have too many Trojans? - I don't think so!
I couldn't resist this one recently when PopeyePete noticed it on the HK "New Items" page and brought it to our attention in our forum. Assembly was mainly straightforward but only because I had a good idea of what was going on - a complete beginner would have a terrible time with the lightweight instructions. The parts, fit, and overall quality are excellent though - I'll install a spare PZ Trojan pilot later to complete it. I spent a while putting fuel-tubing on clevises (which was missing on the flaps and ailerons), tweaking the zero positions of the control surfaces and double-checking everything during assembly and before flight.
It's impossible not to make comparisons with the PZ Trojan: The PZ model has 20mm greater wingspan, and is 5mm longer but weighs 880g stock, as opposed to the Durafly model's quoted 1260g weight!!!! So, the wing-loading is clearly higher. This was foremost in my mind at takeoff. A static test last night showed 330W at full throttle so it clearly had enough power at about 130W per 500g.
There is only about 20mm clearance between the prop and the ground, so I was a bit worried about that too. I set up the throws to make it pretty docile, especially the flaps which only have about 15Deg of deflection. A CoG check with the Zippy Flightmax batteries I had showed it to be about 5mm on the nose-heavy side (I thought that was good for a maiden).
Enough bullshit.
I cranked it up and away it went. The first evidence of its higher wing-loading was the longer than expected takeoff roll. Once up it was solid and well-behaved. The retracts worked perfectly. It has a high roll-rate compared to the PZ on similar throws and it will climb easily. I was flying most of the maiden at about 70% throttle and it was still happy to roll quickly without losing height and looped effortlessly. Low passes at full-bore with the gear up looked great! I got some height and hit the flaps, a slight nose-up but nothing alarming.
Landing was easy, but I didn't use the flaps on the first flight (I wasn't sure how much elevator to mix in). With the higher wing-loading it likes to use most of the strip which is not unexpected. Once I get accustomed to the flaps, this will be more manageable. Obviously with the extra weight, it doesn't float in like the PZ one, but it is nice and steady and predictable anyway, so it doesn't matter.
Overall impression: I love Trojans and this one is very classy for a very modest price!
Update: I've been flying this on 4S 1800 mAh batteries lately, as opposed to the 3S 2200 mAh that is the stock recommendation. I replaced the 35A ESC with a 45A Aeolian ESC I had available because I wanted to keep the nice scale stock prop. It really rips across the sky now, and has unlimited vertical - great fun, but you've got to concentrate because it's not at all like the PZ Trojan in this configuration. It's easy to fly it in a completely un-scale manner, rolling at a ridiculous rate for example. I know that the real Trojan could actually do 629 km/h which is almost 400 mph and is pretty quick for a large machine like that - so I've now got to learn how to try and fly it fast to mimic a full-scale plane at top speed, yet keep the manoeuvres scale. Good fun and highly recommended!
Conditions: Zero wind, overcast but good visibility, moderate strip condition
Aircraft: Durafly T-28B Trojan (1100 mm wingspan, 910 mm length)
Can we have too many Trojans? - I don't think so!
I couldn't resist this one recently when PopeyePete noticed it on the HK "New Items" page and brought it to our attention in our forum. Assembly was mainly straightforward but only because I had a good idea of what was going on - a complete beginner would have a terrible time with the lightweight instructions. The parts, fit, and overall quality are excellent though - I'll install a spare PZ Trojan pilot later to complete it. I spent a while putting fuel-tubing on clevises (which was missing on the flaps and ailerons), tweaking the zero positions of the control surfaces and double-checking everything during assembly and before flight.
It's impossible not to make comparisons with the PZ Trojan: The PZ model has 20mm greater wingspan, and is 5mm longer but weighs 880g stock, as opposed to the Durafly model's quoted 1260g weight!!!! So, the wing-loading is clearly higher. This was foremost in my mind at takeoff. A static test last night showed 330W at full throttle so it clearly had enough power at about 130W per 500g.
There is only about 20mm clearance between the prop and the ground, so I was a bit worried about that too. I set up the throws to make it pretty docile, especially the flaps which only have about 15Deg of deflection. A CoG check with the Zippy Flightmax batteries I had showed it to be about 5mm on the nose-heavy side (I thought that was good for a maiden).
Enough bullshit.
I cranked it up and away it went. The first evidence of its higher wing-loading was the longer than expected takeoff roll. Once up it was solid and well-behaved. The retracts worked perfectly. It has a high roll-rate compared to the PZ on similar throws and it will climb easily. I was flying most of the maiden at about 70% throttle and it was still happy to roll quickly without losing height and looped effortlessly. Low passes at full-bore with the gear up looked great! I got some height and hit the flaps, a slight nose-up but nothing alarming.
Landing was easy, but I didn't use the flaps on the first flight (I wasn't sure how much elevator to mix in). With the higher wing-loading it likes to use most of the strip which is not unexpected. Once I get accustomed to the flaps, this will be more manageable. Obviously with the extra weight, it doesn't float in like the PZ one, but it is nice and steady and predictable anyway, so it doesn't matter.
Overall impression: I love Trojans and this one is very classy for a very modest price!
Update: I've been flying this on 4S 1800 mAh batteries lately, as opposed to the 3S 2200 mAh that is the stock recommendation. I replaced the 35A ESC with a 45A Aeolian ESC I had available because I wanted to keep the nice scale stock prop. It really rips across the sky now, and has unlimited vertical - great fun, but you've got to concentrate because it's not at all like the PZ Trojan in this configuration. It's easy to fly it in a completely un-scale manner, rolling at a ridiculous rate for example. I know that the real Trojan could actually do 629 km/h which is almost 400 mph and is pretty quick for a large machine like that - so I've now got to learn how to try and fly it fast to mimic a full-scale plane at top speed, yet keep the manoeuvres scale. Good fun and highly recommended!
Steve Murray