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Help! Old Thunder Tiger Gull 1800 conversion

#1
Hi. I’m sure I am posting this in the wrong spot but I’m pretty new and had a question or two. Although I have built a simple cub, a long ez, and most recently a speedster. I have not yet flown them because of weather and I’m kinda waiting for nice weather and a friend to help out. Anyway. I have acquired a free plane kit I think from the 80’s. It’s a Thunder Tiger Gull 1800 sailplane. I was curious what size brushless motor would be good to replace the brushed motor pictured. Thanks everyone in advance. Oh. The prop is 8x4.5 breakaway. I’m sure my terminology is wrong.
 

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mrjdstewart

Well-known member
#2
the weight of the plane is what is important. with that then you can figure out how many watts you would need, then you can pick a motor to match.

does it give an AUW? (all up weight)

laters,

me :cool:
 
#4
The box says 1500 grams. I was thinking a park 370 motor with a three cell battery would be plenty of power because it would easily shave off 500 grams of weight. Any thoughts?
 
#6
the weight of the plane is what is important. with that then you can figure out how many watts you would need, then you can pick a motor to match.

does it give an AUW? (all up weight)

laters,

me :cool:
Shaft Reversed!!!
I jumped in with the Park 370 1360kv. I will be building this week hopefully and I’ll share pics and stuff as I go.
Hi. I’m sure I am posting this in the wrong spot but I’m pretty new and had a question or two. Although I have built a simple cub, a long ez, and most recently a speedster. I have not yet flown them because of weather and I’m kinda waiting for nice weather and a friend to help out. Anyway. I have acquired a free plane kit I think from the 80’s. It’s a Thunder Tiger Gull 1800 sailplane. I was curious what size brushless motor would be good to replace the brushed motor pictured. Thanks everyone in advance. Oh. The prop is 8x4.5 breakaway. I’m sure my terminology is wrong.
Hi. I’m sure I am posting this in the wrong spot but I’m pretty new and had a question or two. Although I have built a simple cub, a long ez, and most recently a speedster. I have not yet flown them because of weather and I’m kinda waiting for nice weather and a friend to help out. Anyway. I have acquired a free plane kit I think from the 80’s. It’s a Thunder Tiger Gull 1800 sailplane. I was curious what size brushless motor would be good to replace the brushed motor pictured. Thanks everyone in advance. Oh. The prop is 8x4.5 breakaway. I’m sure my terminology is wrong.
Shaft reversed!
 

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#10
Just finishing touches left!!!
I wanted to close out this thread. The Thunder Tiger GUll 1800 sailplane came out perfect! It flew great today!!! Flew it with a friend over the sand dunes in Welfleet Massachusetts!!!
 

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buzzbomb

I know nothing!
#11
Coming late to this thread. I am happy all worked out well for you. NICE looking sailplane! Welfleet Mass? I googled it. At least you didn't have any water hazards around your flight! :LOL:

Welcome to the FT Forum Family, Pilot!
 
#12
Coming late to this thread. I am happy all worked out well for you. NICE looking sailplane! Welfleet Mass? I googled it. At least you didn't have any water hazards around your flight! :LOL:

Welcome to the FT Forum Family, Pilot!
Lol. Yes!!! If you look you can see where the ocean meets the land the dune provides an updraft! I think I’ll be getting 45 minutes flights. I wish I could post the videos but it won’t accept the videos! All my projects are done and I am in search of a new one!! Maybe I can find another old plane someone tried to build but couldn’t.
 
#14
Hello, I’ve been trying to find someone with the same glider and finally found it!!! I started to repair and change the electronics for a brushless since the old motor was very heavy, I bought the same propeller as you did, but for the motor I chose a 880kv. I was running out of budget and I chose to make my own battery pack of 3s, with Li-po batteries (18650) that I bought for a previous project, I did some testing but I felt like it didn’t have enough thrust and I was scared of flying it and crashing it right away...my question is, will the motor have the sufficient kv or should I get a different one? And about the battery, should I use 3s or 2s? Thank you very much in advance 😊

This is the motor I bought: https://s.click.aliexpress.com/e/nz3RcT9O
 
#15
Good morning. First I just want you to knok I have only been doing this rc flying stuff for 5 months. I do think that motor will be fine. I put a much smaller Eflite park 370 1360 kv on mine and it burnt out in two flights. The motor I used should have been big enough? Please let me know how this motor works out because I need a new one. Good luck stay in touch and I would love to see pictures.
 

Chuppster

Well-known member
#17
Hello, I’ve been trying to find someone with the same glider and finally found it!!! I started to repair and change the electronics for a brushless since the old motor was very heavy, I bought the same propeller as you did, but for the motor I chose a 880kv. I was running out of budget and I chose to make my own battery pack of 3s, with Li-po batteries (18650) that I bought for a previous project, I did some testing but I felt like it didn’t have enough thrust and I was scared of flying it and crashing it right away...my question is, will the motor have the sufficient kv or should I get a different one? And about the battery, should I use 3s or 2s? Thank you very much in advance 😊

This is the motor I bought: https://s.click.aliexpress.com/e/nz3RcT9O
I would think that that motor would work as long as it fits in the nose. Keep in mind, "kv" is not a measure of power but a measure of RPM/V. Now, if you plan to use the propeller that came with the airplane, you do need to keep kv in mind and find a motor to match your prop.

If you look a the product page for the motor, it recommends a ~10x7 propeller. If you put the 8x4.5 on that motor you won't get much thrust because the lower KV motor is designed to use a larger prop. So, I would recommend getting a larger proper or a higher KV motor.
 
#18
I would think that that motor would work as long as it fits in the nose. Keep in mind, "kv" is not a measure of power but a measure of RPM/V. Now, if you plan to use the propeller that came with the airplane, you do need to keep kv in mind and find a motor to match your prop.

If you look a the product page for the motor, it recommends a ~10x7 propeller. If you put the 8x4.5 on that motor you won't get much thrust because the lower KV motor is designed to use a larger prop. So, I would recommend getting a larger proper or a higher KV motor.

The prop size for the glider is 6x4.5. What is the perfect motor for that prop?
 

Chuppster

Well-known member
#19
The prop size for the glider is 6x4.5. What is the perfect motor for that prop?
A 6x4.5? Hard to determine a 'perfect' prop, but you'll need a really high KV motor to make the best of it. Ideally, you'd want a 9" or larger prop for an airframe of that size, but I would guess you'd want something 2000KV or higher for a 6" prop on this airframe. I was thinking it was an 8"...

This is out of stock at the moment, but if the dimensions fit I would say it would fly just fine on 3s.

https://hobbyking.com/en_us/propdrive-v2-2836-2200kv-brushless-outrunner-motor.html?wrh_pdp=2
 
#20
I was wrong. It’s an 8X4.5. But still my park 370 powered the glider fine. Slapped soared way up night over the dunes three times. But the motor burnt out. Also weight is not and issue. I had to put at least 100g of nose weight in her to get the cg right.