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Member postings for David Hall 9

Here is a list of all the postings David Hall 9 has made in our forums. Click on a thread name to jump to the thread.

Thread: DH Tiger Moth 1400mm
20/02/2020 17:21:09

Nice 3D printed tools... I need a strip cutter, can you share the file or location for this?...

Thread: Article on building a LiPo warmer box
07/02/2020 12:02:04

I like the idea of a technical warmer... Warming them certainly makes a difference, particularly for my smaller high C batteries for glider climb-outs. In my shirt pocket, the little packs can get to the high 20's, but for the bigger LiPo's I put them in a (well padded) camera bag with a handwarmer.

Thread: RES Eagle
04/02/2020 14:06:20

Thinking about how to power the Eagle (E-Eagle?)..

I guess that for my purposes, climbing to height on the motor is for sport/practice flying, quite a small power setup would be fine. No-one would care if it took me 40 seconds to get to 100m.

If F5RES ever became a comp class in the UK, what would the likely requirements be?

01/02/2020 16:56:40
Posted by Sussex Pete on 01/02/2020 08:21:58:

Hi David great to know more are on the building board 8) There's a separate build thread at RES-Eagle Glider RCME March 2018 where a few of us are sharing ideas. Someone somewhere suggested building one wing and both Red and RES Eagle fuselages. The glider fuselage will weigh a lot less without motor and Lipo. Also the BARCS 2020 postal competition is off a 60m bungee to fit smaller fields which might work for you?

Edited By Sussex Pete on 01/02/2020 08:24:04

A separate fus is a good idea... For a while, I have been trying to place the two wing bolts at the same place and spacing on a range of my 2m Eglider models (with some level of interchangeability in mind), maybe now is the time to utilise them and build the kit fus for bungee.

Thread: Show Us Your 3D Prints
01/02/2020 14:09:28

Thanks for the links... useful things to be found.

31/01/2020 17:37:26

cowl.jpgpuller.jpgI bought a printer a couple of months ago and have made several household items with it. They have got to be quite cheap.

I made some tools for my modeling, a nice sanding block that uses that 19mm sandpaper on a roll (awaiting a long threaded rod to arrive in the post), a gear puller, which, of course would be useless for anything stuck fast (but is absolutely great for pulling my folding prop spinners off motors) and several thin cowls for my gliders where a replacement motor is longer than the original or to clean up the nose.

All fun learning, I foresee all my servo trays and cowls being made like this. Great for gadgets. As I write, the printer is printing a router jig system that I can use with my Dremel to easily and quickly cut simple holes in foam wings to fit a range of servos.

Wouldn't it be good if we could link or upload our designs here?... searching on other websites seems to be a hit and miss exercise..


Edited By David Hall 9 on 31/01/2020 17:38:51

Edited By David Hall 9 on 31/01/2020 17:40:43

Thread: RES Eagle
31/01/2020 11:34:20

My RES Eagle kit arrived today. It looks good.

As launching by bungee is a problem at my local flying site, practice would be difficult, so I intend to add a motor for practice/sport/F5J flying. I guess there's no reason that competing in F3RES comps would be a problem (with the spinner & props replaced with a simple cone).

I noticed that the box is labeled as "for beginners"... is that the building or flying, or maybe both?

Thread: Just Curious
21/01/2020 19:57:52

Being just a little cynical, it's easy for me to imagine that the local police force might be called upon to demonstrate that they have been out policing this law. Chasing 14 year olds around could be a thankless task, so why not fill two months quota of the number of checks by visiting the local model flying club now and then...

We would all be OK, I'm sure, but the original targets might be missed.

Thread: Dash cams
18/01/2020 10:30:49

I have no experience with rear view cams, but have use a normal. cheap standard dash one and have installed a few for the family.

They can save you money. In an accident where you are not to blame, their use is obvious. Where it's a bump that might show you were at or partly at fault, there may be no need to use it. It has saved me having a minor bump written off as "knock-for-knock" (jointly to blame, because it's one's word against the other..very common), even so it saved several hundred pounds.

I only fit mine behind the shaded area of the windscreen, behind the mirror, so that it peeps out underneath. It's quite discrete. If you leave it on show, stuck in the middle of the screen it will eventually be stolen and cost you the repairs for the break-in.

...... in many cars, there is a 12v feed to the mirror area, usually to power a light or something that is turned on with the ignition. There's also usually plenty of space behind the light cluster, so I have fitted a BEC to those connections and poked the end out to the mirror area. It works very well and is as neat as you could wish for.

Thread: Upgrading Windows7 to Win10 for free
17/01/2020 13:53:42

Keep your old laptop or create a dual boot system so that you can boot up a different operating system (I really like Ubuntu, but that's not the point of this thread....)

There's so much spyware and virus/keycoders out there that I don't feel comfortable running the same system to make financial transactions as the one I browse with and (particularly) receive emails on.

I have my older laptop that is slower than many, but has no extra software loaded (makes it seem faster). This is the machine that I use for anything that I might have to enter financial details via. It is not used for casual browsing, i can browse on my PC and when the time comes to say, buy a holiday, do that on the laptop. I keep the laptop as a secure device.

Keep it clean, don't browse anything but known, trusted sites, make special email addresses for when you "have" to create a login for run-of-mill stuff (not the one you use for finance). Use your regular PC for general use.

Good luck with choosing a new machine. ... I wouldn't know what to offer as I don't know how you might want to use it.. but as has been said, avoid the lower spec/no-name machines, particularly anything with a low memory capacity. Starting point for memory (for me) is 8G and up.

17/01/2020 10:08:23
Posted by Jon - Laser Engines on 17/01/2020 09:33:08:

I cant deny that chromebooks and ubuntu are options but given FN's familiarity with windows and slight distrust of all this silicon witchcraft its probably safer he stick to windows to prevent total confusion. That is why i didnt bother mentioning them.

Also, if you think microsoft is bad at collecting your data through windows then you best not think about what google are doing with a chromebook.

Sorry, I had re-read my post in which I suggested trying a Linux system (Ubuntu), then decided it didn't fit the thread properly and deleted the text before seeing that Jon had added to the thread...... Hope this helps makes sense of the previous two posts. .


Edited By David Hall 9 on 17/01/2020 10:09:01

17/01/2020 09:25:53

edit:   removed. 




Edited By David Hall 9 on 17/01/2020 10:05:17

Thread: Got a motor, what will it suit?
01/01/2020 21:04:44

My club has organised a few indoor flying sessions over the winter. I fancy joining in.

Whilst digging around in my spares box, I found a set of parts for a Syma X5C quadcopter. The motor assy consists of the 7x20mm motor, gearbox and prop all in one unit (see pic). The copter is around 105g and runs on a 1S battery. The prop is 134m diameter.

I fancy trying to build my own mini flying wing in Depron, What size/weight of wing (or any other model) might this motor suit for indoor flight?





(I have ordered a 420mm 3D (trainer) that might take weeks to arrive...)  maybe it will work in that?   


Edited By David Hall 9 on 01/01/2020 21:05:58

Thread: Propeller efficiency
18/12/2019 21:24:03

Thanks guys.... my purpose here is considering a slow climbout of a powered glider, so it may be closer to the static thrust condition than a high speed model.

It's been my observation that there is a marked increase in efficiency as the prop size is increased, but it's not an observation based on measurements. I suspect that the Open class F5J flyers tend to run higher speed motors through a reduction gearbox for the same reason (although the airframes have now evolved so that even a 28mm outrunner wouldn't fit anyway).


Edited By David Hall 9 on 18/12/2019 21:24:49

Edited By David Hall 9 on 18/12/2019 21:25:06

Edited By David Hall 9 on 18/12/2019 21:25:29

18/12/2019 10:53:13

I recall reading (perhaps on this forum) that at the prop sizes we might use, the efficiency (I guess the conversion of input energy to thrust) increases by a few % for each increment in prop diameter....

I can't find the thread now, If i recall correctly, it claimed that efficiency increase by around 5% for every inch increment in diameter when around 10 inches.

Anyone know if there is a rule of thumb for this increase?



Edited By David Hall 9 on 18/12/2019 11:01:09

Thread: Intermittent Throttle Mystery on Spektrum 1S Indoor Receiver
07/12/2019 20:20:00

That looks as if it is having a brown-out. This is where the battery doesn't have enough output to run the motor without a significant drop in it's output voltage, causing the control to reset. It might improve as the battery is warmed up. Fairly typical of an ageing or poor battery.

Thread: Is it Just my impession?
28/11/2019 17:46:07

It's an interesting thread. As an oldie returning to the hobby, I recognise many of the problems.

One thing other thing that appears to have changed is that some threads (this one maybe, many others definitely) claim to build from scratch using a plan. That's refreshing! When I did this many years ago a scratch builder started from ... er...scratch, (ie no plan other than their own). Someone who built from plan was a "plan" builder. Several threads on this forum describe a "scratch" build from plans.

Thread: Another way for props to bite
25/11/2019 15:28:42

I found that enlarging prop mounting holes with a drill was a bit hit-and-miss. It seems that it's quite easy for the drill bit to bite and go through the prop hole not dead centre, resulting in off centre holes.

I now enlarge all my prop mount holes with a tapered reamer. This gives a cleaner hole that has a better chance of being concentric with the original.

Thread: Foam Wing Cutter
15/11/2019 10:50:28

The next time that I try foam core cutting, I'll try this wire...


Thread: F3-RES
05/11/2019 15:25:40

I had the impression that F3J comps were becoming harder to find..maybe others with better knowledge of the comps run in the UK are able to chip in...

The RES class is very attractive as a means of offering competitive aeroplanes that aren't prohibitively expensive, as an alternative to the all moulded carbon fibre airframes that dominate the current Open F3J/F5J/ALES comps (rightly so, as they are superb at what they do in the right hands).

The RES class seems to be more active elsewhere in Europe. The current F5J/ALES comps regularly run around the country allow for a 2m class that runs with the Open class. The 2m class is not as well supported by the top manufacturers as the Open class (>4m) and several affordable models can be competitive. There is no reason that RES models shouldn't be used in these comps (many are, but most seem to be pretty lightweight and so best suited to calmer conditions). For me, it's more about the experience of comp flying than being a contender, although that is beginning to change.


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