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Aug 22, 2017, 06:44 AM
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I had the same problem with landing gear. I just sanded plastic part with sandpaper and glued everything together with epoxy. I added glass fibre inside to strengthen connection inside fuselage. It is working without a problem. Unfortunatelly I have no photos...
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Aug 22, 2017, 06:56 AM
Registered User
Its good to know it isn't just myself. I don't have any fiberglass, I do have some plywood and epoxy.
Aug 23, 2017, 04:00 PM
Registered User

Battery query


Quote:
Originally Posted by jack herr
I am not the best on getting photos and videos posted but, I will get some pics that will show the problem area. It may be a day or more before I get back to it. Yesterday it rained all day so I wasn't able to work on the garage I am building. Today the sun is shining but it is a mud pit around the work site. I will see if I can some pics today.
I actually woke up this morning with ideas running through my head on how to reinforce the area. This is such a fun plane to fly I don't want it sidelined because of weakness in that part.
Jack
Thanks in advance for the photos Jack. I will be giving the issue a lot of attention and will obviously share my own solution once I've figured out how to tackle it!

Adam, it's great to hear that you solved the issue using epoxy and glass fibre. Was the glass fibre a cloth that you used with the epoxy to create a composite? Where did you apply it? As it has solved the problem for you, I'm interested to know what sort of runway you use, is it rough bumpy grass or smooth asphalt (or something in between)?

Could I please pose another question to you chaps in the meantime....BATTERIES!

The recommended lipo is a 265g 2200mah 45c 4s. This will provide a peak of 99Amps max continuous current draw, which seems rather excessive on a 40A (I read that it draws 45A) system. Higher C lipos are obviously more expensive but also usually heavier for the same capacity. I learned on youtube that the stock 2200 gets about 6 minutes, which is a little short in my mind.

What lipos are you guys using and what sort of flight times do you get? How do you all find the CofG with your chosen lipo? Have you moved the lipo or added any lead at either end?

What am I thinking?
Well I have been searching for some lipos which will fit the 110x35x35 stated battery compartment size. Could anyone confirm if different shaped lipos will fit, even with some simple foam cutting? I'm looking for larger capacity lipos that are similar weight to the stock one. I've found the following so far:
Zippy compact 2450mah 35c at 265g. https://hobbyking.com/en_us/zippy-co...___store=en_us
Zippy flightmax 2800mah 30c at 288g. https://hobbyking.com/en_us/zippy-fl...-4s1p-30c.html

I know that the C rating is considerably lower, but because the capacities are higher, the max continuous currents are still very generous (85A and 84A respectively). The 2800 should get roughly 7.5 minutes and this seems pretty good for a 23gram penalty. Is the plane very sensitive to weight in the air?

Thanks guys, I was going to wait for the plane to be delivered so that I can choose the best battery, but I'm keen to get the bird in the air asap!
Aug 23, 2017, 05:06 PM
Registered User
Hello,
Iīm using very nice asphalt runway. I had just one "bad" landing with side wind when plane went out from the runway to the grass. Speed of the plane was probably too high and landing gear "went out" from the fuselage.
I wanted to reinforce ply wood (it is too weak I think) and make good connection between foam, ply wood and plastic part so I use fibre glass with epoxy to create composite. It is possible that now it is strong enough and next "bad landing" can cause bigger damage.

Regarding Batteries Iīm using Turnigy Lipoly and Nanotech 2200 (https://hobbyking.com/en_us/turnigy-...lipo-pack.html).
I have 7 minutes of flight time. Nanotech is lighter than Turnigy but I didnīt change its position at all. It is almost impossible to find difference in flight for me. (Better pilot probably can feel the difference.)
I have good experience with Zippy Compact from other planes so I will probably order one or two 2450mah but I donīt expect longer flight times.
Aug 26, 2017, 04:01 AM
Registered User

It's arrived!!


Very exciting.....

Battery
So I've ordered two 2800mah zippy flightmax https://hobbyking.com/en_us/zippy-fl...-4s1p-30c.html. I'll let you know how I get on with it but was surprised to see that only 1 dimension is really restricted physically. The width and length could accommodate very different shapes of batteries if so desired. I'm sure I'll end up moving the battery further back to make it balance as per stock, I hate forward biased planes and won't use lead if at all possible.

Undercarriage
My idea of using threaded studs up into the receiver compartment with a spreader plate on top looks viable. I'm going with that along with some additional glue for now because the approach is invisible. I reckon the best solution would be to remove the bending loads from that area by using struts or alternatively fitting a longitudinal spreader plate which ties in fore and aft. This would make the pullout forces negligible. I've fitted some larger wheels for the first few flights, I may actually keep them and modify the wheel pants to suit them....

Tail
I can see the problem in the tail but am reluctant to glue it all together because future maintenance would be very difficult. I'm considering using some thin 1mm carbon rods to secure the assembly. Leaving them a few mm proud would allow me to remove them using pliars. Not sure yet...

There were a few areas that needed additional glue but generally the plane has been assembled well in the factory. There seems to be some flex between the control horns and the flight surfaces so I will probably improve that at some point. Figuring out a colour scheme is the next decision!

I will post photos once I have something meaningful to show with the improvements.
Sep 01, 2017, 09:16 AM
Registered User
cbear's Avatar
if anyone happens to crash and total the plane ( not wishing it on anyone ) and has a motor they want to sell let me know, mine is making a humming noise above half throttle , I have had the motor out and have not been able to figure it out, magnets are all in place, bearings seam fine , . balanced the prop, on the ground it powers up fine except for one time it looked like the prop shaft was shaking, in the air its every time i advance throttle past half ,I even resecured the motor mount ,,,,, I wish they made it easier to remove the motor, lock nuts on the back side are a pita to get to
Sep 01, 2017, 11:20 AM
crash expert
could it just be a resonance vibrating through the big flat motor mounting plate? I have a few electric planes that whine at certain rpms and maybe the whine is being amplified by the motor mounting board
Sep 01, 2017, 08:47 PM
Registered User
cbear's Avatar
I think you may be right ,,,,I had a battery eject at the start of a inverted snap roll, the plane spun in from approx 100 ft, minimal damage from the crash , a few cracks and the nose buckled a bit not bad at all considering if it was a balsa plane I would have needed a trash bag . at first I thought I had bent the shaft or a magnet came loose so I pulled it apart and it looks good ,so after the repairs off to the field and first thing , buzzzzz , ,, the strange part is if I power up full on the ground its fine but in the air at half throttle its a very loud buzz and a reduction in power ,I even resecured the motor mount thinking as you said a possible vibration from metal mount, but I may have missed something , possible broken foam around the mount ? I'm going to take it apart again this weekend cause this is just too nice a flying plane to have sitting collecting dust
Last edited by cbear; Sep 01, 2017 at 08:53 PM.
Sep 08, 2017, 05:09 PM
Registered User

Tail Stiffening


Here are a few photos of the approach I used for the tail stiffening. I didn't want to use glue as I prefer to be able to easily disassemble. I used cf skewers. Some are not shown in the photos, particularly between the horiz and vert stabs. It seems pretty solid so far....
Sep 08, 2017, 05:13 PM
Registered User

Undercarriage Strengthening


I decided to strengthen the undercarriage before my first flights because my runway is quite rough in places. I used two threaded rods about 100mm long to replace the mounting screws. They go through cf spreader plates and are secured with nylocks. I've run over a few larger weeds and some wheel deep holes without issue so far....
For the initial flights I fitted some larger wheels. I quite like them so will probably fit the wheel pants over them before I paint.
Sep 08, 2017, 05:18 PM
Registered User

CofG and Electronics Layout


I use 2800mAh lipos which are 20g heavier than the stock 2200mAh. I also use 3 different alarms to help me find the plane if I ever lose it. They add around 15g. The CofG would therefore be further forward than it should be and I don't like forward biased planes - I much prefer neutrally balanced planes. I therefore needed to move the battery aft in order to balance the plane. The photos showed how I did this, adding some battery straps and a foam block at the forward end. The battery is solid.
Sep 08, 2017, 05:38 PM
Registered User

Beautiful First Flights!


The first flights have been very impressive, with no serious issues. I flew on low rates for most of the flights, whilst I became attuned to the different flight characteristics and a few minor issues.

The plane flies beautifully, I'm very impressed! It has a good amount of power, is beautifully neutral and there is clearly a wide flight window... I have so much to learn. Every landing has so far been perfect, even on the rough terrain. It seems to just touch the ground and stick to it, no bouncing, ground loops, or anything else. It does land fairly fast as expected and I found that my spoilerons massively help with reducing the landing speed and getting the plane down smoothly. I needed to add 10% up elevator to the mix with the first stage of spoilerons; I haven't yet tried to land with full spoilerons.

I found that my Lemon rx generated some oscillation when I tried the auto/panic switch - it might have been caused by the rx being slightly loose (why on earth did I mount it on Velcro?!) or the gains being too high for the speed of the servos - i'll find out on the next flight. The wind speeds were low so I didn't really need any assistance, but I need to sort it out for gusty conditions and as a panic button.

I'm trying to decide what colours to paint the plane - it really is difficult to fly at a distance when all in white. Orange and blue should contrast rather well....

So far I'm loving the experience with the HotTrigger! Well done Graupner! I have lots of plans and ideas for it, but clearly need to take the developments slowly so that I can develop my 3D and aerobatic skills in line with the ability of the stock plane.

Last point - I measured the power on the ground: 772W, 49A, 16.65V (note that these numbers don't tally and most measurements were 46A....maybe a spurious reading?). This is rather high for a 40A esc!! I gather that other owners have measured 45A. I recognise that in-flight current will be lower but it is rather concerning....I wonder how long the motor and esc will last....Cbear, did you ever resolve the issue with your motor vibrations? Some dynamic balancing might identify the issue. If you decide to replace the motor, would you consider upgrading it? I plan to measure the motor's resistance at some point, in order to line up a more powerful one (a few months down the line I imagine)
Last edited by procat; Sep 08, 2017 at 06:18 PM.
Sep 08, 2017, 08:17 PM
Registered User
cbear's Avatar
hey Procat , very nice review .., mine is still in time out , for the past few days my wife and I have been going thru all our belongings trying to get ready for irrma, Naturally all my models had to be moved upstairs because of the flood risk, my luck is the roof will blow off with no flooding ,,,I had no idea I have collected so much rc stuff lol. you mentioned painting yours and the orange one the flight test guys reviewed looked fantastic, as far as upgrades go I may install a torque 2817 motor in mine and drop down to a 3 cell pack,, right now that motor is in my timber and its looking like it may get retired soon , it has a 14-6 prop on it , full throttle burst are kept at ten seconds and I think it may be a nice combination for this airframe if I cant get the bugs worked out on the stock unit ,,,, to be honest the stock setup was imo pretty dam sweet just the way it was as long as the battery you use has a high C Rating ... well.. except for the need of a 4 cell battery ,... I do like your velcro battery tray you made , i'm definitely copying that as soon as this storm passes , reading your experiences with this plane makes me want to get busy
Sep 09, 2017, 04:33 AM
Registered User
Wow Cbear, best of luck with getting through the hurricane unscathed tomorrow. Hope to hear more about your Hottrigger once things have settled down for you. Procat
Jan 13, 2018, 03:56 AM
Registered User
Quote:
Originally Posted by Adam85
Hello,
Iīm using very nice asphalt runway. I had just one "bad" landing with side wind when plane went out from the runway to the grass. Speed of the plane was probably too high and landing gear "went out" from the fuselage.
I wanted to reinforce ply wood (it is too weak I think) and make good connection between foam, ply wood and plastic part so I use fibre glass with epoxy to create composite. It is possible that now it is strong enough and next "bad landing" can cause bigger damage.

Regarding Batteries Iīm using Turnigy Lipoly and Nanotech 2200 (https://hobbyking.com/en_us/turnigy-...lipo-pack.html).
I have 7 minutes of flight time. Nanotech is lighter than Turnigy but I didnīt change its position at all. It is almost impossible to find difference in flight for me. (Better pilot probably can feel the difference.)
I have good experience with Zippy Compact from other planes so I will probably order one or two 2450mah but I donīt expect longer flight times.
Nice picture!


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