Large Model Association Forum

Hi,

Just thought I'd share some pictures of the model I'm building at the moment. I'm at the stage now where I need to start finding some of the components, in particular retracts. I'm looking for electronic retracts rather than air, which is not the easiest to find, so if anyone has suggestions they'd be greatly appreciated.

Rudders and belly fins now added, so the next job is control surfaces.

Hobbyking electric retracts for max weight 20-25kg 107000214-0 £125

Full Metal 90 degree Servoless Retract Set - High quality CNC alloy servoless retract system for large models weighing up to 20kg , features all metal construction for precision, reliability and durability, also features auto cut off for protection against excessive current draw.

Spec:
Pin size: 8mm
Weight: 160g each
Max Model Weight: 20~25kg
Operating Voltage: 4.8v~7.4v
Speed 6v: 6 seconds / 90 degrees
Speed 7.4v:5 seconds / 90 degrees
Base size: 86x59x36.5mm

Thanks Steve, have you used them or seen the quality. My experience with Hobbyking in the past has not been the best if I'm honest.

This looks like an interesting project.
Question, where do the plans come from?
And the laser cutting?

As for retracts, you get what you pay for.
I would not trust my landings to be fully intentional with HK retracts.

Kjell

Thanks Kjell,

I'm more of the mind set of buy quality, buy once, so I'll be the same over the retracts.

The plans were originally a scaled down copy from Tony Nijhuis of the one Steve Holland now flies, though I did re-draw them electronically myself for the laser cutting, as well as making a few design changes for flying on electric power rather than petrol.

As for the laser cutting itself, I used to teach at a university, so cut it all myself before I left.

Chris.
I used to have a YT bronco of similar size, converted to electric, weighing in at around 38 lb flying weight. I used electron retracts, the er50 versions. I also use these on my current 1/5 scale tucano (er50) and my long time owned YT thunderbolt (er40). The thunderbolt in particular has been fitted with these retracts for about 4 years and not a single issue, no appreciable wear and 100% reliability with regular use even in the winter. I heartily recommend them. They are a bit more expensive but are on a level with Sierra giant scale in my opinion. Several different angles and steering options. I built my own gear legs. Here is their site.

http://www.electron-retracts.com

I am a great fan of the Bronco, what is your estimated flying weight, sadly the YT version is no longer available. I would really be interested in getting a kit from you, any chance??

thanks.

Dave.

I would look to Hawe in Germany for retracts.
http://www.hawe-modellbau.de/english/

I have seen myself some real nice OV10 retracts from Hawe, but it is only listed in their German PDF.
According to this, they have 4 versions, designed for 2.2 , 2.4, and 2.8 meter wingspan Bronco.

Kjell

Thanks all, I'm liking the look of either Robart or Electron at the moment to fit the bill, just need to do some calculations to see if the 100 degree angle from the Electron is enough for the front wheel, I may need 105 degrees to get the front wheel fully inside once up.

Dave, I'm aiming for 28-30lbs if my calculations are all correct, but I expect a few extra lbs to sneak in when I'm not looking, so it may end up around 32-35lbs in total. I'm afraid I'm not in a position to produce a kit for you, as I no longer have access to a laser cutter etc, so this is a one off.

If you can supply a plan, then it can be sent to Chris at Slec, where he can scan it and cut a kit for you with no probs.
Slec do it for me regular, and they are always turn out right !!!

Having been very busy building a couple of projects for work over the last year, it was great to be able to put some more time in on my own Bronco this weekend.

Not a massive amount done, but then it's not a race. This weekend I built the elevator control surfaces, as well as finished one of the rudders.









I've split the elevator in to two halves, partially for redundancy, but also to make it easier to set up later with two separate servos.

Some more progress the last week or so, as the tail sections are nearly complete.















I have also fed the servo wire extensions through ready to connect, as I don't fancy trying to put these in later.

I also need to add a wire for the beacon light that sits on top of the horizontal stab.

I still can't resist the odd test fit as you go along, it really gives the idea of the final scale.

Friday evening I had some time to finish skinning the underside winglets (not sure if they have a technical name).







Before skinning I also added a little bit of wiring, as this would be complicated once skinned.

Adding the dowels for attaching the front fuselage.

Starting further work on the tail booms.

















I still need to add the bottom skin for the booms, but I want to get the retracts first so I can make sure of the mounting etc. No point adding the skin only to cut it off again to make changes.

Those winglets do have a tech name, sponsons

Looking really good Chris, would love the full story for the Journal if you ever fancy having ago. My contact is at the bottom of my posts and in the Journal.

Good luck with the rest of the build.

Dave (LMA Journal Editor)

Steve Perry wrote:Those winglets do have a tech name, sponsons

I knew they'd have a technical name, but although I love model building my aircraft knowledge is limited to the physics (voodoo magic) of how they fly.

Dave Parry wrote:Looking really good Chris, would love the full story for the Journal if you ever fancy having ago. My contact is at the bottom of my posts and in the Journal.

Good luck with the rest of the build.

Dave (LMA Journal Editor)

Be happy to write something up once it's all finished and we can get the important flying photos.