Hi,
I have an electric glider which has
Wing Span 2,6m
Wing Area 55dm^2
Cruising Speed 60km/h
Engine/Propeller static thrust about 2,2 kg
I just weighted my plane and it was 2915g (wing loading 53g/dm^2). I could reduce some weight of the underlined items so that the total weight would be 2660g (wing loading 48g/dm^2)
Last winter the plane weighted 2350g (wing loading 43g/dm^2) and I was able to launch it from the hand. Do you think I should consider some sort of landing gear to launch the plane or do you think that I could still launch it from the hand? Does anyone have experience what kind of wing loading
48-53g/dm^2 is in reality?
Frame
Wings
Canopy (foam -> thin plastic)
Wing strut tube (aluminium -> carbon)
Attachment sockets (nylon -> carbon)
Power and data cords
6000mAh 4s battery
115A ESC
Radio control receiver
Radio telemetry transceiver
GSM telemetry transceiver
Ixus camera (new lighter camera 190g -> 130g)
APM1
APM housing box (acryl -> balsa)
Magnetometer
Air speed sensor
Wing and Tail led lights
Lightning battery 3s 250mAh (battery removal -> lightning power from the main battery)
Replies
Ηι Veikko,
with 48-50gr/dm2 WL, you practicaly have a light trainer, so you can hand lanch for sure but you will loose the glider characteristics (near 40's) glide ratio, stall speeds, ascent rate etc.
As for the "diet"
-acrylic housing its very goodlooking.. but i dont thing you need a housing in a foammy at all.. plus its very very heavy (120gr??)
- do you really need this 110A esc, it seems huge 75-90gr ( a 60A esc is about the half)
- if you consider updating your equipment, APM2,5 its like a feather!! compared with APM1
- with 6A Battery and 8A for cruise speed (at least) you will be able to travel for 30-35min safely -> so with 60 kph CSpeed which is very high, you will be able to travel for 15km max.. Do you really need the GSM Telemetry?
- More Voltage (cells) gives you less Amp consuption, but you carry one more cell.. and 6A 4s battery weights a lot! have you calculated any 3s- more glider like- setup? with less capacity you- less weigth- you will might achieve better descent rates and propably fly more. For example, my plane can carry with eas 10000mah battery, i use it for mapping with a camera like yours, but i realised that iam staying 20 more minutes when i make two flights with 5000mah batt than 1 with 10000mah.
regards
James
We have been hand-launching a 2.5m electric glider with wing loadings up to 72g/dm^2. with success- although at that loading there is no room for error when launching.
You have better a static thrust-to-weight ratio than our heavy glider (static thrust 2.0kg, AUW 3.6kg) so if you're confident launching at 43g/dm^2 I would say don't worry too much and give it a try.
Cheers
Rich