Su-35 360 VT

Ротор

Hi Jandro!
Perhaps there is some risk to fly with goggles without seeing the aircraft from the ground. May be flying through the screen is more safer. What is your opinion on this issue?

RC4ever

It first depends on what is your flight range.
If you are going to fly close, maybe screen is more secure but if you are flying farther than 400-500m you won’t either see the plane so there’s no point in using screen.

If you intend to use a head tracker, you need the goggles too. With goggles you are more inmersed and concentrated on flying and thus you can fly safer.
It is also difficult to properly see anything on a screen with daylight unless you cover yourself and the screen with a towel, in which case you also loose sight of plane.

So I think it’s safer to fly with goggles but if you want to be even safer you can ask a friend pilot to be your copilot and keep always track of the plane while you fly so that you can give him the transmitter if you loose video signal.
You can also do this with teacher-student cable to be faster.

In any case, what will give you more security in flight is to use good equipment (Diversity receivers, multiple Rx good adequate antennas or GPS tracker antenna, OSD + Autopilot…)
This way you first ensure that you have more range but if anything goes wrong you can still hit autopilot or “return home” and wait for the plane to come back until you regain video signal or eye contact.

This, of course, is just my opinion 😉

About the Мотоустановка, I was using the original fans that came with the kit, all posted videos are with these fans. Thrust to weight ratio was about 0.7

This past weekend I installed and tried new engines, Counter-rotating Lander DPS 68mm EDF for 6S Li-Po.

rc-castle.com/shop/product_info.php?products_id=20…

I did some thrust tests and this is the outcome:

SU-35 09/03/2013

Weight
Plane + Rx Batt: 2460g
Main batt: 805g
TOW: 3265g

CG (with gear out)
145mm from CG to wing LE on wing-fuselage joint
170mm from Cg to wing LE on wing’s LE end against body

Measured Thrust on ground: 2200-2300gr

__________________________________

SU-35 19/05/2013

Weight
Plane + Rx Batt: 2744g
Main batt: 841g
TOW: 3585g

CG (with gear out)
148mm from CG to wing LE on wing-fuselage joint
173mm from Cg to wing LE on wing’s LE end against body

Measured Thrust on ground: 2800-3200gr

Please, I insist that you keep speaking in russian!
I will translate and ask by private message if I have any doubt, maybe this way I can learn something! 😁

ElephantXP

То-есть насколько понимаю, с лендеровскими импеллерами тяга всеравно меньше 1 получается?

RC4ever

It would be better to have more than 1 to 1 Thrust to weight but it’s very difficult in this plane. Maybe you could do it using 8S LiPo capable motors in PLASTIC fans to reduce weight and improve power.

I bought the lander fans because they are the only high power counter-rotating dynamically balanced EDF set that I know and is sold at a reasonable price.
The all-metal shroud sadly increases the weight a lot 😦 but they are also very efficient 😆 so I can fly more time than if I use 10-12 blade EDFs.

Ротор

Hi Jandro!
Thanks for yuor opinion about FPV system. I think that flying with copilot using second transmitter is a good idea. Motors for Su-35 is a problem. I think there is no good proposal on the market. When you measured stock EPF trust did you use 10 or 6 blade fans?
When do you need to use tailarons for roll? You said that ailerons should be used with great caution.

RC4ever

Это правильно. It’s difficult to find a good combo for this plane, you will get best performance with 5 to 6 blade lightweight and dynamically balanced fans like Wemotecs, eflight V15 housing or some tamjet models (more expensive)
As for the motor, you could try with HET 2W35, Eflight BL32 or Dr. MadThrust 2200kv for 6S LiPo. There can be better options for sure but I don’t know them.

I measured thrust for stock fans with 6 blades. Lander turbines have 5 blades instead.

As for ailerons, you can use them normally like in any other plane but above 30º angle of attack, use of ailerons can lead wings to stall. If you have tailerons and ‘roll - TV’, you need less surface deflection to accomplish the same and they become safter to use (Harder to stall). But sometimes, the use of rudder just works better at high alpha flight.

Болшоые спасибо за терпение!
Напиши мные, пажалуста, по русски. 😉

Всего хорошего!

smg2000

У него обороты больше, а мощность меньше…

ElephantXP

но он на 3-4 банки расчитан. На 6S мощность вырастет некисло. Другой вопрос, долго ли протянет 😃

smg2000

Надо экспериментировать на стенде. Можно же и 5S на него дать.

ElephantXP

Есть конечно вообще красивое решение. Найти умельца, который перемотает штатные движки на больший KV и мощность. И с весом проблем не будет, и тягу можно будет поднять. Но где такие умельцы водятся, мне пока не известно. Слышал, что они существуют, и перематывают движки за разумные деньги под любые хар-ки

ElephantXP
smg2000:

Можно и такой попробовать. У него внешний диаметр 72мм и тяга 1800г
Только надо будет мудрить с диаметром сопла

Покумекали и пришли к выводу, что если перевести модель на 5S, то может получиться либо больше 1, либо (если потери в трубе будут слишком велики) то очень близко к 1 при заметном уменьшении веса. Но и поколхозить с установкой придется немного.

RC4ever
ElephantXP:

Интересно, что будет, если в штатных импеллерах моторы заменить на вот эти hobbyking.com/…/__21482__NTM_Prop_Drive_28_36_2700…
сгорят или можно пробовать?

I wouldn’t use anything under 22.2V (6S Lipo) on this plane. 500W is too little power to be able to drive this plane. Besides, even if you managed to pull 1200-1300W (Like the lander fans) you would be drawing a LOT of current to get that power! Remember P = V x I, if you lower Voltage you need more Intensity.

But more intensity means you are emptying the battery very quickly so at the end you don’t loose weight using a less cells battery because you need to increase its capacity (More mAh) and then, if you need more current also need more powerful ESCs and anyway you’ll be loosing a LOT of energy in heat dissipation.

So, you always want the higher the voltage you can get because you reach high power with very few Amps, and that is way more efficient.

High voltage - high power motors is the way to go for EDF. 😉

This is some crazy user’s setup from another forum (although expensive 😵), I’m quoting jcdfrd from RCGroups:

"Fan Shroud: TJ70 7 stator
Rotor: CS 12 blade dynamic balanced
Motor: NeuMotor 1117 2250KV
ESC: ICE Lite 100
Lipo: 7s 3700mAh

_Bench measures:
2650 watts @ 110A
Thrust 6.7 lbs
RPM 46,300
Efflux velocity 248 mph
Exhaust tube 58mm
TJ70 PNP weight 15 oz"
_

ElephantXP

Вот это уже похоже на тягу в районе 1 или чуть больше 😃 А какой аккумулятор использовался? И сколько весит этот импеллер с мотором в сборе?

RC4ever

T/W thrust to weight ratio with Lander Fans: about 0.9
I’m not really reaching 1:1 due to airflow friction losses on ducting 😦

I keep using Haiyin 6S LiPo 5000mAh 30-40C battery.

Combined weight of the two EDFs is about 600gr

Thrust is like 2,9-3,1 Kg

ElephantXP
RC4ever:

Haiyin 6S LiPo 5000mAh 30-40C battery

Этот аккумулятор весит примерно 800 гр. Если взять фирменный подороже, то будет 700. Вот и 1:1 уже станет реальностью!

8 days later
RC4ever

What LiPo brand sells a 700g 6S 5000mAh battery?

Sounds interesting!