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Tony Nijhuis Hawk - Build Log


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Now got the fan blade fitted. It was described as a different make but is in fact the same. Problem was that when tightened up it jammed, but grinding 2mm from the rear to match the original sorted it. A lot of work to replace the damaged wiring and get everything installed again but I am more or less happy with it bar getting the main batteries in a position to get the cg correct.

Gave it a run up over wooden decking with luggage scales connected but despite having cut a very large cheat hole am apparently only getting 2.25kg of thrust. Tried digi kitchen scales on the nose and the reading was similar.

I then tried it on longish very soggy grass and it at least started to accelerate. Tried putting my thumb nail in the exhaust edge and the revs seemed to increase a lot with a better jet like sound just as I did with my Gnat. No readings taken though.

Where do you propose to put your Rx and the servo batteries? As you can see from my pics I have masses of wiring and clutter which I have kept as much as possible out of the airflow.

It will be quite a while now until the weather calms down and the patch dries out enough for taxiing trials.

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Hi Martin

Out of interest, what happened to your original fan blade causing it to shatter?

The plan with mine (at the moment) is to fit the receiver and servo batteries up against F2 with access via the cheat hole.

I have been waiting ages for H-King to get their Life Zippy receiver batteries back in stock and can't decide between 2 x 700mah or 2 x 1100mah. The first option being lighter but possibly a bit low in capacity - What are your thoughts Martin?

Regarding your thrust measurements, what batteries and 'C' rating are you using? If they are Multistar's (which I seem to remember you mentioning in another thread), might the 'C' rating be a bit low?

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Hi Geoff, I already admitted earlier to running the fan with the wing off and sucked in a 10w connector!

I have fitted 700 LiFe packs but they may not be big enough to drive 10 servos plus retracts. Could maybe steal some 1100s from other models.

Main batteries are 2x 5c Zippy compact 5800, 25c

Just been re looking at the cg and have had to push the packs way forward so will need to extend the mounting plate and the wiring a little.

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At a bit of a loose end I have now made some changes. I originally had twin rudder servos either side of the fan in order to reduce any impediment to the airflow but have instead fitted a HS80MG in the centre. Also swapped over the ESC, switch/ RX mounting plates to get the cg a little further forward. I now have one battery in the normal position and the other on the opposite side up to the front former. This puts the cg in the correct place and allows a bit more airflow. I have had to extend the ESC to fan wires plus some short 10 AWG ones to connect the packs in series. It is ready to go apart from the 700 Rx packs. Weight is now 11.4 lbs. Ouch.

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Geoff,

Yes I will do a build log for sure. I haven't built a plane since I was a child, that was a Precedent Hi-Fly 2. Recently I've been concentrating on helicopters, but I do have a Wot 4e that I fly about with. So this will be a challenging build for me.

Martin,

Nice photos, I look forward to hearing how your maiden goes.

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Thanks for the pics Martin.

Little bit more done on mine:

I made up some base plates for the air intakes and glued them on using canopy glue. Then made a paper template for the cutout, attacked it with the drill and sanded smooth.

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I have also 3d printed an exhaust ring and glued that on with canopy glue.

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More later...

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  • 2 weeks later...
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A few more bits done:

I have given the wing a coat of sauce and sanded back, also added the anti stall fins (which I nearly forgot).

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Installed the anti roll fins to the bottom of the fuselarge. I made a jig to help get the angle correct.

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I have also designed and 3d printed a pair of air intakes that will be fitted to the top hatch.

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More later...

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Hi Martin,

I've been using Freddy B's Sauce on my Bella Ballerina some years ago now.

If you visit page 43 of my build blog, there it is... yes

@ Geoff > yes please, if you have your notes at hand, I would be very interested in your parts weight progression...

Cheers & keep careful, gents

Chris

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