Chris Walby
-
Posts
2,807 -
Joined
-
Last visited
-
Days Won
3
Content Type
Profiles
Forums
Blogs
Gallery
Calendar
Downloads
Everything posted by Chris Walby
-
I have an electric ME109, easy to build and flies will, but rather old school and not very fast (I am pushing 840w/lb). There are name sake and far eastern versions that are more up to date, cheaper and faster! IMHO
-
Thanks for all who have contributed...I'll read through in detail and digest, then see if it helps with what I have.
-
General question for the model gurus amongst the forum as I suspect there is no specific answer, but its opinions I am after. I assume some aircraft are more tolerant of C of G movement and some less so, my question is what affects this? As an example I have a foam EDF that is 1500mm long, AUW 2.5Kg and its C of G moves backwards when the gear goes down by close to 25mm. From gear up to gear down this causes a noticeable pitch change (which with a bit of mixing I can sort out if I can keep it in the air long enough!) and sensitivity. It’s the sensitivity change which is the surprise/hard work aspect. If I move the C of G forwards I reduce the sensitivity, but with wheels then up run out of up elevator Examples of aircraft C of G tolerant and non-tolerant please?
-
Andy, You probably know already, but just in case I would not be too tempted to have a lot of surplus power (remember power corrupts and absolute power corrupts absolutely!) . What I mean is mine does swing a bit on take off , but is easily corrected and is off the ground in no time at all. if you have an excessive amount of power it will be more work keeping it under control and the risk of snapping the throttle open and getting swing/roll will be harder to manage. PS I like my 3 blade prop, looks nice and gives good low speed performance. If I need speed my FF ME109 at 840w/lb will suffice, but boy does it have a wicked roll on launch! Let us all know how you get on with the build, cheers
-
I would have thought the larger diameter and lower pitch prop would be the way to go assuming the airframe can swing a prop diameter you want (ground clearance). The other limiting factor will be the amount of power the engine produces over its rev range. If to put too larger prop on it will create too much load across the engine speed range and not allow it to rev out. You could try the 23x8 (if you have one) and see how it goes (that's 2 inch diameter and two inches on pitch) which it a lot more load on the engine so it might not pull it. Better to get a 23 x 6 if you can...or 3 of 4 blade and same pitch as they should be okay at low speed. PS Jon might be on holiday, but he is watching
-
Andy, Well I few it today although it was a bit murky there was very little wind, result as it was really nice Adjustments made prior to flight were: Moved clevis's to maximise servo movement for correct control surface throws (as per manual) Moved C of G about 3mm further forwards than manual states It nosed over on taxi after a greaser of a landing (much better than the Wots Wot flight prior!), plus was on high rates as well Conclusion: I messed up with too much elevator travel and not enough expo from previous attempts to keep the tail down Flight on low rates is very sedate and gear + flaps 1/2 caused no issues (although with a bit of head wind it won't be a problem anyway). Full flaps don't look that severe but might make it more work than they are worth as it flies in smoothly anyway. If you want my TX setting PM me. Both of us at the field remarked that due to the colour scheme it looked like a silhouette most of the time and I would recommend the maiden on a nice bright day until you get used to it! Thanks to Jon and Martin for their helpful advice, cheers PS how are you getting on?
-
Forum members' new models: Let's see them.
Chris Walby replied to Paul Marsh's topic in All Things Model Flying
Levanter, Very nice looking model and with that weight reduction I am sure it will fly well. Most impressed with the colour scheme and let us all know how it looks in the sky! -
Why would it be piracy the product is protected by the dongle not the software. I have it loaded on two PC's but can only ever use it on one as I only have one lead. PM me and I'll post you my disk if you want.
-
Any news of finding out what the issue was....
-
TWS, Yes and no. Yes its the same watts, but the greater the current the higher the losses especially if you are pushing high currents. My other point is the motor is directly affected by the applied voltage, so a low KV motor and low cell count means you need too swing a big diameter/pitch prop to get similar thrust 320KV motor on 5S with a 16 x 10 three blade prop drawing 37A and 3.1kg static thrust 560KV motor on 5S with 13 x 8 three blade prop drawing 65A and 3.3 kg static thrust So will a 59 inch Hurricane look scale with a 16 x 10 prop or a 13 x 8? In this case with a 800KV motor with low cell count should not be an issue. PS I don't think they are quite the same physical size either. PPS not forgetting the max current is a product of the c rating and the capacity Edited By Chris Walby on 23/05/2018 15:02:27
-
Martin, I'll recheck the C of G and see if I put the mark on the fuselage for the battery location in the wrong place, but looking at the photo the U/C looks well forward and not forgetting it has larger than standard wheels/no oleo covers to catch the grass. Arc, What's the KV rating of your motor? mine is 580KV on 5S with a 3 blade 13x8 prop pulling 65A although it does not need quite that much however if you are using 4S you'll be dropping the motor speed by 16% which is a big drop in thrust or hike in current + not sure if you will get a much larger diameter prop on it and it look scale. I initially tried it with a 320KV motor and a windmill of a 3 blade prop (looked pants) and just about made its way around the sky with little margin for anything (Martin might remember the experience as he was on the sticks). What lipos do you have? If you have 6S to hand you should be ok, might be worth remembering I am running a 3 blade prop so does more of everything compared with a 2 blade the same pitch/diameter.
-
Why do you need to take it apart to find the size, the 70 and 80 are quite different and the sizes are on the Laser Web site . Plus the prop nuts are different sizes between 70 and 80's, best send it to me and I'll check it out in my BH Speed Air (goes like the clappers with a 70... but with an 80....ooorrr
-
Hi, My AUW is 3.1Kg and I though the manual says 2.8 so not to far off. Don't be confused by all of the manuals on the web for its bigger brother that's more popular with the IC guys. Ground handling is very good on grass (short-ish) with a bit of expected left swing on take off. Landings on flaps 1 are okay, can't remember using full flaps as it flies quite slow anyway. I am the biggest problem and I think once I have sorted the servo travel out and taken a bit of elevator travel out it will be really nice. Its a good size as I don't have to take it to bits to transport . If the servo travel doesn't sort the flight issues out I'll push the C of G forwards a bit, but bear in mind the club guru liked it as it was...
-
-
Hi, Built (well as much as you can with an ARTF!) and can't say I am that impressed with the covering quality (not as good as previous BH models IMO). Resident club guru did the maiden and trimmed it in with a couple of clicks here and there and pronounced "nice". I have flown it a few times and have had problems with it due to the following reasons (most self inflected!): Reduced servo travel (TX) to get the correct throws - needs to be mechanically correct Does not need that much elevator to induce a lot of pitching motion - fixed by the above and less travel Flies ok until I put the gear down and flaps 1, then gets very pitchy Best and last - due to the shape/matt covering and in poor light it becomes at best a silhouette (well no surprise really) so fly close until you get use to it My setup: motor 800KV Overlander 1280W with 80A ESC on a 3 blade 13 x 8 (more than enough power) on 5S4500 lipo Summary, nice plane, quality good and flies well although a bit of a challenge for me, but then again life would be boring if everything was just easy. PM me if you want anything from my build. What retracts are you going to use + any idea's on your set-up? Edited By Chris Walby on 22/05/2018 16:07:23
-
Not flown the Dual Ace much, but the 12x8 (noise reducing and restricted throttle opening) seem to go okay if not a little pitchy at low speed, but no issue. Looks like good news with the C of G at 130mm and should be spot on with the Lasers up front bearing in mind the Dual Ace came out "light! with no added lead compared with Seagull's stated recommended 2S 46's and lead to get C of G. I am meant to be getting a few hours in before swapping the Lasers across to the mossie and of course the Dual Ace will look so sad missing a couple of 70's.....What should I do?
-
Electric motor not running with prop attached
Chris Walby replied to FilmBuff's topic in ESCs (Speed Controllers)
I had a similar issue and it was the manufacturers soldered (lack of solder) connection and the bullet which was masked by their heavy duty heat shrink sleeve. Best strip back and inspect as its only the time and a bit of heat sleeve to do. -
Danny, thanks for your frank comments as its really useful for the rest of us and I agree with all of what you have said. I have a couple BH Mossie 's which have a 4S5000 as far forwards as possible which is a lot for a 2.5kg model and one with an additional 270g of lead to get C of G. I feel your pain as its really hard with the mossie getting weight forwards, but what about ali spinners (ail does not weigh much, but the steel nut is a far forward as you can go Could get a heavy version!). Unfortunately I learnt the hard way trying to land slow (3 blades and full flap had very high drag) so IMHO quicker and at worse a go around rather than tip stall at 25ft with gear down is a better option. I am sure you have been through this, but if C of G is at 130 mm where does it end up with gear down, just gives options knowing that C of G is at "x" with gear up and "Y" gear down should things start to get a handful in the air and you need to revert to different setup. All the best and keep posting
-
Danny, wow that's 1.1 Kg over Sea Gull's max weight, although it will just mean that you will need to fly it a bit faster. Odd as there is nothing in the RC Universe article saying they needed to an a load of lead and their AUW was very close to 6.4 Kg at actual 6.46 Kg. Just how much lead did you need to add to get C of G? Teaching you to sick eggs, but is there anything else to could more forwards like ESC's, RX + anything else.... Let us know how you get on and thanks for posting.
-
Wots Wot pilots electric power?
Chris Walby replied to Vinegar Dave's topic in General Electric Flight Chat
Its a while ago now, but I don't recall having any issues with implementing the electric set up I describe above. Operationally it has proved fine - I know some don't like the battery retraint method - but I have no problem with it. Basically I built two extra trays (copying the first) and three batteries are perminantly allocated to this model, taped onto those trays. I change the tape every couple of months that's all. BEB IMHO I have to beg to differ, as standard the banjo style hole and nylon screw is a accident waiting to happen as it will only be a matter of time before it will come loose and the battery fall out (been there, had that). The mod is simple and does not affect the original design so you can make a couple in case you loose one, just far better than major rebuilding in my book . -
Wots Wot pilots electric power?
Chris Walby replied to Vinegar Dave's topic in General Electric Flight Chat
V Dave, don't do it !! IMHO its a very low KV motor and I think you will have to swing a big diameter/ pitchy prop to get the performance you want. Mine set up is Motor Dynamic 5055 680KV 1280W 80A, 80 ESC, prop 14x8.5 (85% max load) on 5S4500 Will climb vertical and flies a treat PS from my testing for a 320KV on 5S on a 16 x 10 three blade (the biggest I have!) gave me 37A and 3.1Kg static thrust + will look like a windmill ! PPS - Again from experience there is a flaw with the battery try retaining method....but an easy fix. -
Craig, Apologies as off topic, but this may become an issue for some. Sorry to say I have had the complete opposite experience with my foam EDF. It needs high ground speed to get air over the control surfaces to take off and mine has a forward C of G (due to the canards!) plus the nose wheel is was directly below the 6S4000 lipo in the cockpit The original plastic U/C self destructed on the first launch run and I am now up to version 2c as it did very good impressions of a high speed "Reliant Robin Roll" or mad ground squirrel. The issue (I think) is too much ground clearance (I lifted mine by 15mm on V2, but lower on V2c) and sloppy steering. I have added a ball joint and extra bracket on the oleo pin and got rid of all of the play, but one issue as that the rod that connects to the oleo pin could slid up and down, but that changes the steering direction ! IMHO its down to power to weight and technique, I can't pussy foot about on grass with a long winded acceleration down the runway, its up to full power, charge down the runway and gentle climb out to get air speed up (grass can be very high drag even with larger than standard wheels). This means that when it goes pear shaped it does it really fast and the result is not pretty, but its the only way of getting EDF's off the deck. My forum post is under "Steering nose leg does it need trail" if you want to take a look. Mark, Thanks for the comment, I am interested due to the geometry change between retract positions (up vs down) and if there was any rotation of the oleo + how the steering servo copes when the oleo is retracted as the ball joint end needs to slide along the oleo pin. Edited By Chris Walby on 16/05/2018 09:14:09
-
Mark, Very nice build you have going there, thanks for posting. Just noticed on this photo you have a small L bracket on your steering rod, I assume its to stop the ball joint end sliding down oleo steering arm pin and changing the nose wheel direction. Have you used this setup before and is it tricky to set up regarding aligning it all in the up and down positions? Thanks for your time and keep on posting
-
Jon Prop hanging a 10lb Hurricane,,,,, brutal and possibly not very scale Although a few years ago at Little Gransdon a full size Hurry put on a cracking display and the low passes blew the spit display into a cocked hat! I don't know what the power increase between a 70 and an 80 is, but I think you are right an 80 will do just nicely.
-
Ron, Thanks for the weight info, I must admit I am slightly surprised it came out at 3.5kg as my BH Speed Air is 2.8kg with a Laser 70 in it (11x7) and that will do unlimited vertical so an 80 in a 3.5kg AUW model (25% different in weight and 15% in engine capacity). Not so sure you'll be able to climb out of prop hangs easily, but with the wing area and wingspan it should be a good use of your 80 and fit a 100 when one becomes available. I still think you will have a really nice model to fly.
