Here is a list of all the postings Gordon Whitehead 1 has made in our forums. Click on a thread name to jump to the thread.
|Thread: If I fit floats to my Senior Telemaster will I need a more powerful engine?|
If you're going to fly sometimes with floats and at other times with the land u/c, you need to take steps to ensure that the model's CG is always correct for the configuration in use without having to add or remove balance weight during the changeover. If you forget to make the balancing weight adjustment, you might end up with enough of a rearward CG to lose the model in an unintentional low-level spin.
I speak from experience with my one and only floatplane conversion of a model which usually flew as a landplane.
It's likely that the extra lift from that portion of the floats in front of the propeller will require weight added in their noses to move the model's balance point a tad further forward in floatplane configuration as compared with landplane configuration. So you should set up the model's CG for its landplane configuration first. Then, having established where the CG should be for the model as a floatplane, add weight to the floats permanently so that when converting from landplane to floatplane, the CG will be automatically correct the instant the floats are secured in place. I didn't get around to adding permanent balance weights so that through a moment's inattention when adding the floats before (its final) flight which my Dad was going to video, I forgot to add weight to the model's nose, with the eventual unfortunate consequence mentioned above.
Your flaps should come in handy for taking off from a smooth unruffled water surface. Never having seen mention of this, on the first flights of the model I eventually lost, I scooted the model around to create ripples per the conventional advice for aiding unsticking. Eventually, I discovered that lowering the model's flaperons, which I had always used previously for take-offs in landplane configuration, negated the need for ripples, so I lowered the flaperons for all future take-offs.
|Thread: Best DV11 plan|
My own Fokker DVII is a lovely flier. The plans, and building instructions together with extensive flying notes are also available on Outerzone. The model is compact enough to be stored and transported fully assembled.
Edited By Gordon Whitehead 1 on 09/01/2020 17:28:30
|Thread: BMFA News Dec 2019|
Well said Ken. Three 3 more from me too
Edited By Gordon Whitehead 1 on 07/12/2019 19:11:29
|Thread: Catapult Build for Ducted Fan Models|
If I understand correctly, you stake the bungee elastic down at both ends at right angles to the line of flight, and then fasten the cord linking it to the plane at the centre of the elastic. This then has the effect of preventing the bungee elastic being deviated by the wind. During launch, which doesn't take long of course, the model on the end of the linking cord will be pushed a bit sideways by a side wind, but far less than if the cord was in line with the whole length of the stretched elastic.
We fly on a narrow field bounded by trees, often with cross-winds, and if that idea works well it's worth bearing in mind for future reference. The only possible downside seems to be that there are two bungee stakes to try to miss on landing
BTW, I think I also saw another thread about the Miles Student in your avatar. I can't remember if it was ducted fan or pusher, or which forum it was in, but I do enjoy reading design and build threads. After partaking in this thread I'm beginning to feel like having another go at a li'l EDF, having had much joy from the little ones several years ago. Must finish my current bipe project first, though.
Re the H-K bungee setup, there's a video here which shows how to set it up and avoid some possible pitfalls. The ends of the ramp are designed to not snag the wing undersides, so I stand corrected there. Whether the distance between the ramp rails is compatible with the distance between the nacelles on a 52in span Canberra is something to consider, and could be cured by changing the lengths of the cross-tubes. The safety pin mod is worthy of note, as are the comments regarding tailplane clearance, and ensuring the bungee pin is well pushed down. Personally I'd use a screw picket/dog stake for that job.
Hope this helps
Hi Steve, thanks for your video which explains the foot release very well. It's a very clever design and looks to me to be more foolproof against accidental launches than the pin-through-a hole style of the H-K foot pedal.
I love your Sipa Minijet, which I believe you featured in a recent build thread. It brings back a memory of my Dad taking me to an air display at Yeadon Airport in the mid 1950's. The display included a handicap air race which had everything from piston bipes to a couple of jets, one of which was the Minijet, the other being the Miles Sparrowjet. I can't remember which was the faster jet, but a vision of the little egg-shaped Sipa flashing along at near to nought feet is still imprinted on my mind. One of the bipes was a Blackburn B-2 and there must have been a Tiggie or two as well. Leo Valentin, the "Bird Man" was there but his launch plane had engine trouble so he never got off the ground.
Hi Steve, your ramp is very impressive in its apparent simplicity. Do the rails pivot up with as the foot release is pressed? What is the bungee material, and how long is it and how much do you stretch it?
A safety note for Roy's benefit which I intended to mention before is that a very secure bungee stake is essential. It's not been unknown for the stake to come out of the ground when the bungee is stretched and come flying back to hit the operator.
The Hobbyking kit doesn't appear to include any means of linking the bungee to the foot pedal and model, and there's no instruction booklet in the pics. Plus I can't see how the pipe joiners won't carve chunks from the wing undersides as the model exits the end of the ramp. A length of pipe insulation on the rails would prevent this risk to damaging the model.
Another note about the bungee stake. It's worthwhile marking it with some sort of flag. We'd carry the bungee etc to the flying site in a supermarket bag, and fix that to the stake to blow in the wind. This highlights where the stake is in the ground so that at the end of a flight you don't crash the model into it on landing.
Edited By Gordon Whitehead 1 on 12/11/2019 09:30:11
Edited By Gordon Whitehead 1 on 12/11/2019 09:36:56
Not so my Frightnin' seen here
That has to be the most relaxing-to-fly supersonic fighter ever, Ray
Another variation on the Bobsleigh ramp was that of his club-mate Terry, who used a pasting board that not only conveniently folded for storage, but also had a carrying handle. Owing to Terry's seniority we called this one "Gramp's ramp" !
The next pic shows solarfilm base of slipper.
Next pics shows recesses in packaging foam to accommodate bungee ring and fuselage hook.
I used this ramp for many years. We called this one "Gordon's Grasshopper". If the grass is long, the stake cord passes over an A-frame. The frame is just two laths of wood linked by one screw as a pivot, and the cord passes over the vee at the apex.
Launch sequence follows. Note wing supports for Lightning, and also the way the nose dips at end of ramp as model pivots on tank - cured by later use of slipper.
Model seen on ground is Ron Laden's scratch-built Eurofighter Typhoon. Ron shot the launch and flying pics during one of our many enjoyable EDF flying sessions using this ramp set-up.
Edited By Gordon Whitehead 1 on 11/11/2019 14:43:36
The ramp is a 1/4in thick exterior plywood board with folding legs and which is sized to fit on the floor of the car boot with the rear seats folded forwards. The legs fold so that the ramp takes up minimal space when laid in the back of the car. The point of using a board is that planes on which the tail is lower than the wing such as the Lightning, TSR-2 etc risk catching the tail on the framework of a pipe ramp. This eventuality cannot occur with a board.
When set up for launch, note how the rear legs elevate the back of the ramp so that the release cord follows the same slope as the ramp.
The ramp slopes at no more than 10 degrees.
I measure bungee tension with a spring balance, and use 4x model weight, ie a 3lb model has 12lb bungee tension.
The Hunter pics show wing tip supports from pipe lagging and the Lightning needs taller supports which peg into the edges of the board seen in later pics.
The Lightning needs the slipper seen in the pics. Without the slipper the belly tank pivots the nose down when the plane reaches the end of the ramp. The slipper is made from foam plastic with a solarfilmed liteply base. It only flies about 3ft from the end of the ramp during launch.
If I’d fitted the ventral strakes to the Hawk, that would have needed the slipper too.
Here’s my bungee launcher based on a design by Bob Partington which we dubbed the "Bob Sleigh". The pics show the components of the bungee cord and ramp. These days I prefer the pin in tube method over the ring and hook, having broken a bungee hook previously.
Pic below shows pin-in-tube launch connector in Westwings Hunter.
The foot release uses a yacht cam cleat. The sideways foot movement does take a bit of getting used to, but there’s no ring. There’s a risk that elasticity in the stretched foot release cord can flip the ring forwards and wrap the cord round the tailplane during launch. The plate is secured by two tent pegs, and the third tent peg acts as a safety catch, only being removed just before launch. The cleat is secured to the plate by two 5mm screws into T-nuts.
Next pic shows cam on point of releasing cord as trigger is moved sideways with my foot.
|Thread: Martyn's Chippie RCAF 671|
Well Martyn did take the Chippy to Ashbourne and flew it a treat in quite blustery conditions. The model handled really well and Martyn gave it a pretty good wringing out. It looked as if he'd been flying it for some time, so I was surprised to learn that the first flight of several at Ashbourne was only the model's second time in the air, replete with loops, rolls and stall turns. A great big WELL DONE is in order!! The model looked so neat in flight that I now think that I too need a Chippy!
|Thread: Ashbourne 2019|
Another grand day's flying at Ashbourne Chris, and thanks again for organising a most enjoyable event.
Hi Chris, I'm looking forward to another super fly-in tomorrow . See you all there.
|Thread: Latest CAA Update|
The reason that her mention of security stuck in my mind is that it was part of one of her put-downs to our BMFA, LMA etc representatives and aeromodellers in general which said that the DRES scheme was coming, we could do nothing about it, and she didn't see why her taxes should subsidise the system.
Baroness Vere in one of her comments I read about on this or the other thread.
Edited By Gordon Whitehead 1 on 30/09/2019 19:18:18
We are being led to believe that we will be required to register our models for national security reasons. It occurs to me that not registering all flyable drones and models in circulation will leave a gap in their traceability and render the scheme less effective, if not actually worthless, for security purposes.
Thanks Martin. I skimmed the page too quickly.
Some modellers have said that they plan on not registering until next year, presumably with their models in storage somewhere. If the models are in storage then the owner will be responsible for them and their safe keeping. I wonder if that will mean that the owner should register from day one as being responsible for the models per the first line of the Operator ID section, even if they're not to be flown for a long while.
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