Pushy Cat fast electric pusher plane build

[Swale]

wow looking good how long before we see these 2 bad boys in action?

[simonh]

wow looking good how long before we see these 2 bad boys in action?

Per my last post - mine should be ready in a week or two. Gareth's is on hold for the time being due to other commitments. It should be good for 130 - 140 mph - if I'm man enough to fly it at WOT. Should be one of the quickest planes at the patch....

[andyb]

...Andy B - if you are willing, I'd very much appreciate your help with the maiden 

Be happy to - but you can launch it! Better count your fingers carefully afterwards, though 

Should be one of the quickest planes at the patch....

Hmm. I wonder how fast a large EDF will be?...

[simonh]

Have done some more build....

The baseplate for the wing has been covered and trimmed - then epoxyed to the underside of the wing. This effectively sandwiches the wing to the Fuz for added strength.

The first pic shows the base plate ready for glueing. The larger of the 2 holes is an air vent for the motor and ESC. The small balsa assembly in the pic next to the baseplate is the vent cover - wot I made. I need to sand, shape and cover this before epoxying to the underside. The smaller hole is for the elevator servo extension lead. Not sure what to do with this as it will be bigger than necessary after i have run the wire through.  Maybe i could glue a small piece of balsa into the inside of the fuz and fill it??


The next pic shows the underside after the baseplate has been epoxyed in place and the underside of the nose covered.


The last pic shows the positions of the Rx, Battery and ESC. The Rx is an AR600 - more channels than I need for this model but got it for a good price. After connecting up the motor I test ran it at WOT with the 4.7 x 4.7 prop. Oh My God - that is one mad motor - a real screamer  Almost 1kV more than the Mega 16/15/4 on my Stryker B. With the 4.7 x 4.7 prop it produces a crazy amount of thrust for a model of this size. The motor didn't rip itself from the mount - which is good.


The maiden will be entertaining I think. I'm glad I volunteered to risk my fingers hand launching it while AndyB does the first flight and trimming etc.  Andy - bring a spare pair of underwear!

Next jobs are to cut the push rods to size and make Z-bends. I need to make a battery base plate from some ply and make a finger grip for hand launching. All the wiring needs to be routed properly and tidyed up. I still need to do the decals for one of the booms and some stripes for the underside of the wing. After that its setting up the control surface travels and making sure the ailerons have an equal amount of travel, then sort the C of G.

I'm hoping to get it finished during the week for a possible maiden next weekend  - weather and Andy's time permitting.

[simonh]

Quick update - control surfaces have been set up and wiring routed and tidied. Travels set to 3mm low rate (50% of what is recommended on the plan) and 6mm high rate. Expo has been set to make the travels as linear as possible.

Here the bit that shows how little I know about plans - there is a mark on the plan that looks a bit like a radiation symbol. I remember Gareth mentioning it  - is this the C of G? It looks to be approx where the C of G should be.

Ran the motor at high speed for a while - it gets really hot. Planning to drill some holes in the rear hatch cover to supplement my air vent - and maybe the sides of the rear of the Fuz near the motor as well?? Thoughts on this very welcome

Only things left are to make the battery mount, sort the air vent cover and finish the decals. Then I'll do the C of G once I am sure of that mark on the plan. After that, a quick going over with the covering iron to tidy up some of the edges of the covering and we should be good to go.

[andyb]

Here the bit that shows how little I know about plans - there is a mark on the plan that looks a bit like a radiation symbol. I remember Gareth mentioning it  - is this the C of G? It looks to be approx where the C of G should be.

Alternate quarters white and black? That's the one.

Ran the motor at high speed for a while - it gets really hot. Planning to drill some holes in the rear hatch cover to supplement my air vent - and maybe the sides of the rear of the Fuz near the motor as well?? Thoughts on this very welcome

It'll probably need some forced ventilation, but I wouldn't recommend making lots of small holes because they won't shift as much air as one big hole. What sort of air intake have you got at the moment? Any chance of a detail picture?

[Swale]

agree with above id defo make a scoop!

[simonh]

My 'Cat is pretty much finished. Battery mounting plate has been made from 3mm lite ply and epoxyed into the base of the fuz along with a couple of velcro straps.




I've also made a scoop - using Andy B's suggestion of using a cut off plastic spoon to get the correct shape. This will provide cooling for the ESC and motor. I've opened up some holes in the motor mount to allow air to flow across the motor and out.


The finger grip has been made. This was made by sandwiching together two pieces of 3mm lite ply. Grooves were dremmelled on the insides of the ply to allow carbon tubes to be epoxyed in place as locating pins. This needs to be glued onto the base of the Fuz.

All I need to do now is paint the scoop black, paint the finger grip, sort the C of G and it will be ready to maiden. I'll post once more in this thread once we have done the maiden. Will try and get some pics and a vid of it at the patch.

[Swale]

make sure you let us know when the maiden is id love to see this one

[simonh]

I thought I'd finish this off with a quick report on the maiden yesterday. After 3 months or so - two of those working on it with Gareth and the last month finishing it off myself, I had it in a state where I thought it had a decent chance of making  a flight.....

AndyB kindly agreed to make the first flight and Gareth also came down to the patch straight from his holiday. This allowed me to chicken out of both the hand launch and the first flight!

Gareth gave the Cat a good throw and Andy took it up. C of G was a little too far back so it was landed after a couple of minutes. Swale provided 21g of self adhesive lead and we took it up again. Gareth again gave it a good throw and Andy took it up to a safe height for handover. It looked to be flying really nicely - very smooth and responsive without being too sensitive. Andy handed me the Tx and I took it round a few circuits.

It does fly very well - not as fast as I was anticipating but it is very nice to fly and looks great in the air. It will fly very slowly without any problems and the stall is very predicatable and easy to handle. Landing is just like the Stryker - turn it into wind, cut the power and let it glide in for a soft belly landing.

I'm going to fix some wet and dry sandpaper to the finger grip to make it more grippy and easier to hand launch and put a couple of decals on the bottom of the wing to aid visibility and orientation.

Andy suggested increasing the fin area a little for better tracking and I could fit a slightly bigger prop if I want a bit more speed. Andy has also kindly offered to search his vast stocks for a latch to save me scewing in the battery cover.

For now, I'll leave it as - is and get used to flying it. It will be making regular appearances at the patch from now on. Flight time is approx 6 minutes from a 2200mAh 3S lipo.

Thanks to Andy and Gareth for help with the maiden  - ensuring it made it though in one piece. Also big thanks to both for help, advice and support throughout the project.