Dynam Hurricane

[Geoff S]

I bought one on eBay this morning and nipped round to the seller, who lives barely 4 miles from me, and picked it up. It's unflown as yet (by anyone) and the seller has gone to the trouble of fitting flaps. It looks really well.

My usual 4S packs are 4AH and I've had to minor carving to get them in and they fit very neatly with little trouble. Unfortunately, despite the fact that they are completely forward of the CoG it's still tail heavy. The CoG is about 12/15 mm further back than the 65/70mm recommended in the instruction sheet.

I can obviously add some lead but it's hard to find somewhere to put it safely. Has anyone else had such a problem and, if so, how did you overcome it? Do physically smaller batteries (ie 3 AH as specified) help as they can be all further forward?

I am testing without the prop fitted but , whilst that will help a bit, I can't see it making that much difference.

Geoff

[Denis Watkins]

C of G measured with the retracts Up Geoff ?

[Geoff S]

Yes. I don't have a receiver fitted and I need to change the battery connector on the ESC. This is just a preliminary check to see where I am.

Geoff

PS Managed to lower the u/c using a servo tester and it made very little difference.

Edited By Geoff Sleath on 28/02/2017 14:41:15

[Bill_B]

Hi Geoff, I lifted this off the RCGroups web site; "I added weight to the nose inside the plastic vent ..can't remember how much .. but I balanced at 60mm cause my pals one was real tail heavy at 70 . I'm using a 2200 ..gives good 7mins of flight .. watch out on take off for left torque ..she doesn't like to be rolled out on high power"

There is a lot more info over there on the Dynam Hurricane thread so it could be well worth a gander.

Edited By Bill_B on 28/02/2017 14:43:55

[Denis Watkins]

I helped a colleague set up, and he had the 2200 smaller batteries, and 2 x 10grm stick on weights at the forward end of the battery bay.

There were no other issues Geoff, and after trimming it flew beautifully.

[Geoff S]

Thanks, gentlemen. I had a look at the RCGroups web site and it seems experience in this respect varies. Some people have no problems getting CoG in the right place and others do. I seem to need 60 grams with my 4S 4AH packs so quite a bit of extra weight needed up front. It's just a matter of where to put it - easier said than done but I have a few ideas. I have feeling that variations in EPO density in the mouldings might give the variation - denser foam will have more effect at the tail than the front.

A heavier prop nut is one idea and I've sent off for some M7 steel full nuts to replace the half nut supplied. I'll replace the ally washer with steel and perhaps even make a lead washer to go behind the steel one. I wondering if a weight at the end of its shaft might damage the motor. I suppose, if it's balanced then it should be OK. Heavy prop nuts are sold in the US (Harry Higley) but I haven't seen any in the UK.

All reports say that this Hurricane flies well so I haven't lost hope. Main complaints seem to centre on the esc and fragile retracts so I'll see.

Geoff

[Geoff S]

I test flew my Hurricane today in reasonably gentle breeze (10 mph?) but it was a beautiful early Spring day with warm sunshine and daffodils and blossom in flower on the drive over to the airfield. For the first session this year I couldn't have wished for a better day.

With a 4S 4Ah LiPo installed the all-up weight is 1.75 kg. Current draw WOT is 36 amps (476 watts) so plenty of power. As the recommended LiPo is a 4S 2200 it's perhaps a little overweight. Even with the bigger battery (which is all in front of the CoG) I had to fit in a further 35 grams (including a steel prop nut) to get it balance properly.

Anyway it flew really well once trimmed out (just a little right aileron and down elevator but just a few clicks) and I think the extra weight may have helped because it didn't seem to be blown about much. Rolls and loops were OK and just a little down elevator for inverted. I didn't push my luck for a spin. Landing was a greaser with no tendency to nose over on our tarmac runway.

There are flaps fitted but I didn't try them out. In any case they weren't needed.

Geoff

[Dane Crosby]

I obtained mine a few weeks ago. I'm still assembling the beast.

I have shaved out the battery space which was not wide enough.

The throws and centreing on the control surfaces was all over the place.

The landing lights are red so changing them to white.

Re glued the canopy magnets They were loose with little glue.

Chucked the non scale exhausts. I'll make correct ones, with one or two stubs made out of lead to balance her if necessary.

The ESC was rattling about the fuselage. I have refitted it forward under the plastic grille, which hadn't been glued properly.

Otherwise, apart from painting a moustache on the pilot, it will be ready for flight test soon.