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Member postings for DavidKP

Here is a list of all the postings DavidKP has made in our forums. Click on a thread name to jump to the thread.

Thread: 2 blade prop to 4 blade calulation
31/10/2017 19:09:22

Sorry if if this has been covered before but ......

I am building the Lindsay Todd 'Flycatcher' from the free plan and following the excellent build blog on here. At some point there is a suggestion that maybe a 4 bladed propellor would be better for the plane for performance and looks. So how do you calculate the size of a 4 blade prop that has the same thrust as a 2 bladed? Is there a web site or do you guys have some magic formula?

Thread: Questions after maiden flight today
14/10/2017 20:18:16

Should have said that we moved the LiPo about 5mm forward before the first flight so that 'Nico' was happy that the CofG was towards the front end of the range on the plan which is where he prefers it. But no it was never 'twitchy', it flew smoothly but just nose up. Anyway, I will add the washers as advised, and buy a couple of different propellors on Saturday morning and let's just hope that the weather is as good as today, 20 degrees and standing around in a short sleeved shirt in mid-October ..... just great

14/10/2017 18:43:47

The weather was glorious today in Northern Switzerland, and after getting through the shopping with the wife I was able to get to the field with my new Chapter One build by 4 in the afternoon, would have been a bit sooner if I hadnt left the TX behind and had to go back for it.

Anyway, the model was shown to the club expert Mode 2 flyer and he agreed to make the maiden flight. After 2 circuits he said he was having to hold in too much down elevator so brought it in to land. A few turns on the clevis and it was back in the air, flying nice and level on about half throttle, but every time he opened up the throttle it was climbing at an alarming rate. He landed it again and there was a discussion among the club pros, in Swiss German so I couldnt understand anything. At the end the recommendation was to add more downthrust, 2 degrees, by adding washers under the top mounting bolts, and changing to a 'slow flight' propeller, something with less pitch.

The motor is an AXI 2814/16 which is rated 1035 RPM/V, the LiPo is a 3S 3800 MaH. The recommended propellor on the AXI site for a trainer aircraft is 9.5x5. I remember when I bought the motor in the local shop that I had written down that propellor size, but they didnt have any in stock, so the sales guy assured me that a 9x6 would be just as good, up on one measurement but down on the other. So I bought and fitted an APC 9x6 Elektro.

The plane is built with the downthrust indicated on the plan, does it sound right considering the description that I have given that another washer added to the top bolts will help?

And what would be your recommedations about changing the propellor size and/or pitch?

Thread: Forum members' new models: Let's see them.
04/10/2017 20:21:49

I am a slow builder so this has taken more than a year, Chapter One with aileron wings

BUT

First build for 45 years

First build with electric power

First build with ailerons

First build with the iron-on covering, so dont look too hard at the engine bay sides or wing tips

Will maiden this weekend if the weather is right

20171001_152847.jpg

Thread: building bench
24/09/2017 13:08:41

I have contact lenses for normal day wear, helps with the long distance vision and driving at night in particular.

Then in the office I have to wear glasses on top for using the computer but I also have another pair of glasses recommended by the optician for working on the models when you tend to have things closer to your eyes than the computer screen on your desk.

My workbench is a piece of wood on an old IKEA desk, some jobs are better done sitting down but some I like to stand at, so for that the plane comes up as well. Didnt want to spend all of that money on one those fancy adjustable plane stands, so I cut the appropriate shape into the top of two cardboard wine boxes and I find that having the plane up that height above the standard desk height is perfect for me. And I have a ready supply of replacement boxes for the next plane that I build

Thread: Help Needed to Reverse Motor Shaft on Axi 2814/16
16/09/2017 18:05:48

Sorry if this is a silly question but .....

I have the RCME model flying workshop special from 2015 and on page 107 there are instructions for reversing a motor shaft.

I would like to do this to my Axi 2814/16 V2 motor to get the rotating shaft out of the area where all the wires from the ESC and LiPo are located.

No problem to remove the circlip as shown in photo 2, but no sign of any grub screws as shown in photo 3. So put the motor over a hole in the workbench, bit of wood over the drive shaft and hit it gently, then not so gently, but no movement at all. So what could still be holding it in place that I havent seen.

I tried the Axi web site but couldnt find anything

Thread: After 30 years of marriage
10/09/2017 18:47:08

We celebrated 39 years this summer ...... some ups, some downs, but no regrets

Thread: New generation of Fake Spektrum Receivers
03/09/2017 20:56:50

Tom

I am sorry but I do not see the difference between your definitions of a fake and a low cost copy

Presumably if you bought a Porsche without an engine then it would be fake, but if it had an engine made by Hyundai then it would just be a low cost copy.

Sorry

Thread: A new building board
23/04/2017 14:59:36

I had to pick up some things at the big Do-It-Yourself place yesterday, and being alone I could have a good look around. I passed by the 'offcuts' bin in the wood cutting area and there was a piece of MDF, 120cm by 40cm, 10mm thick, one side is faced with the usual white plastic finish, but the other side is covered with 6mm of cork. I have no idea what it was originally intended for but it makes a great building board, nice and heavy, absolutely flat, will never warp and the pins go in beautifully.

Thread: Maiden Desk Flight
09/04/2017 17:35:44

OK, so I know that it is not finished, but I could not resist taking some photos when I got all of the controls hinged up and the wing seating area more or less done.

20170409_122413.jpg

20170409_122812.jpg

Still need to shape all of the control surfaces to the correct profile, fine tune the wing seating and give the whole thing a good sanding before I can start the covering.

Weight as shown with motor and 4 servos installed is 780g, so with the ESC, 3S 3400MAH LiPo and the receiver that I am planning on that comes to 1110g before the covering and linkages. Is this in line with a completed all-up weight of 1250g?

Thread: Cocktail stick through mylar hinge
26/03/2017 18:36:51

Yes ...... it is too late now, the area in question now has the tailplane glued on top and piece of 5mm ply and tail skid underneath.

I have read about these 'furry' hinges but have not seen them for sale in the shop, so I just followed the plan, it's only 3 years old so still up-to-date in my eyes. I will definately put in something as a pinning solution, losing the rudder in mid-air doesnt sound like fun.

26/03/2017 16:58:37

I have read that when you use the mylar hinges it is recommended to drill a hole through and push in a cocktail stick, trim it off and add a drop of cyano. This makes sense when the hinge is going into nice big flat sheets of balsa. But the plan I am using has a rudder 18cm high, the top two hinges are going into the sheet tailfin, no problem, but the bottom hinge is going into the fuselage below the tailplaneand elevator. At that point it is only going into a 5mm thick cross sheet between the fuselage sides. So do you recommend that I still drill across the 25mm wide fuselage a few millimetres behind the cross sheet and push the cocktail stick stick through the gap? Or do you just rely on the glue?

Thread: The Warbirds Replicas Macchi C.202 is Landing!
19/03/2017 16:59:36

That looks amazing, might just be tempted to buy one of those and put it away for a few years until I feel confident enough to attempt it

Thread: Wonderful Words of the past
19/03/2017 16:53:49

Dave Hopkin, "He couldn't stop a pig in a poke" - meaning the he was bandy legged

I always heard that as "He couldnt stop a pig in a passage"

"Dont buy a pig in a poke" meant dont buy anything unseen, a poke being a cloth sack.....

19/03/2017 10:11:31

When playing cards or dominoes and someone had blocked her next play my mother would say "You're like a rat up a spout", never did understand what she meant.

Thread: What's flying over your house
18/03/2017 17:32:14

Yes Peter .......it was worth it.

Thread: Another Shop Going?
18/03/2017 16:57:01

I am still lucky enough to have two good model shops within a 20 minute drive. I may have to pay a little more for each item and it can sometimes be frustrating to have to wait until Saturday to get something that I forget last week. But I like to see things and touch touch them and compare with other manufacturers before I buy. I have never bought anything over the internet.

Thread: What's flying over your house
18/03/2017 13:13:27

Just had one of the Swiss Air Junkers JU52s go over. What a glorious sound. Heard it coming and went out onto the terrace in the light rain, neighbour across the road did the same and lots of grinning and thumbs up signs to each other. Got a right earful from the wife though when I went back indoors in soggy slippers.

Thread: Fixing wheels to the undercarraige plate
12/03/2017 12:21:39

So I got the dural undercarraige plate delivered and bought some nice wheels yesterday. The U/C came with four woodscrews, two bolts, four nuts and two washers. I think that the bolts are passed first hrough the wheel, then a nut added tight enough that the wheel doesnt wobble too much, then through the U/C plate and the final nut tightened up against the plate to hold everything steady. But what is the purpose of the washer? Where should it be placed in this sequence?

And the dural U/C plate is shiny on one side but has a dull white plastic on the other side, that is just a protective layer that I should remove right?

Thread: Chris's Bella Ballerina HD
26/02/2017 18:14:51

Come on Chris, you and Gaston have made such a tremendous effort to make this beautiful model, you cant stop now. I have been following the build since the start, just didnt have anything to contribute so didnt post anything, but I have learnt a lot from your work. Dont know how much I will carry over to my own builds, but those exhausts, I have to copy them soon ......

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