The Janowski Project - Rethinking the J1B/J2/J3

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Ried

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It looks like you have good progress. Thank you for sharing where you're at in the build.

Two questions:

1. Could you clarify what you mean by center of gravity connections? Do your CAD images show added reinforcing on the two fuselage formers? Have you increased the size of the wing and strut attachments?

2. Original J1 engine was made from two 250 c.c. motorcycle engines splice together to make a 500 cc twin cylinder nominal 25hp engine. My thoughts are 40 hp might be adequate, maybe 60 hp is overkill? Only my opinion, no calculation to back it up. (Edit to correct up to hp)

Keep up the good work. I wish you success in getting this project flying safely.
 
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asadof

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It looks like you have good progress. Thank you for sharing where you're at in the build.

Two questions:

1. Could you clarify what you mean by center of gravity connections? Do your CAD images show added reinforcing on the two fuselage formers? Have you increased the size of the wing and strut attachments?

2. Original J1 engine was made from two 250 c.c. motorcycle engines splice together to make a 500 cc twin cylinder nominal 25hp engine. My thoughts are 40 hp might be adequate, maybe 60 hp is overkill? Only my opinion, no calculation to back it up. (Edit to correct up to hp)

Keep up the good work. I wish you success in getting this project flying safely.
Thanks dear friend
Unfortunately I do not have photos to show right now. But I will send at the right time
An engine between 30 and 45 hp is enough
If you observe the weight. Between 130 and 150 kg
I use Google's translation, I do not understand some words, I apologize
 

Ried

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Thanks dear friend
Unfortunately I do not have photos to show right now. But I will send at the right time
An engine between 30 and 45 hp is enough
If you observe the weight. Between 130 and 150 kg
I use Google's translation, I do not understand some words, I apologize
No apologies needed for not speaking English, I do not understand Farsi, either.

I understand you will plan to select engine power as you determine aircraft weight. Be careful to keep it light, and you should be ok.

I will try to re phrase my questions later.
 

Jimboagogo

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Hello friends
I am building this project in Iran
Of course, I have also made some changes. The original design is not reliable. There is a possibility of breaking the body against gravitational forces !!! So I made changes, some parts were strengthened
View attachment 119535
I always liked the looks of the JB1 and 2. Please do keep us posred on your progress. Have you chosen an engine yet?
 

Ried

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Seems to make sense, but I don't see any obvious changes to those bulkhead. I do not know how he made it stronger. Or why the change was made.
 

BJC

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Seems to make sense, but I don't see any obvious changes to those bulkhead. I do not know how he made it stronger. Or why the change was made.
I couldn’t tell whether or not structural element dimensions were changed.

I’m curious; is there an operational history that drove modifications?


BJC
 

asadof

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Seems to make sense, but I don't see any obvious changes to those bulkhead. I do not know how he made it stronger. Or why the change was made.
I sent you a message
I do not know if it will be sent or not
 

Ried

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I sent you a message
I do not know if it will be sent or not
I did see the first and will check for the second.

I would prefer this discussion stay public. People here are smarter than I am, and will correct me if I give incorrect information.
I couldn’t tell whether or not structural element dimensions were changed.

I’m curious; is there an operational history that drove modifications?


BJC
An operational issue I am aware of is an old discussion if there is enough elevator authority at low speed. This can be a problem trying to flare during landing.

If I do decide to build a J1b, I want to investigate adding a LONGER fuselage for longer lever arm on elevator. A T-tail (like J2) would help by placing elevator in the propeller blast. And I think this issue makes keeping a careful watch on the center of gravity location.
 
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Ried

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Asadof,
In post 199, you attached a video of the landing gear being tested. It seemed to work well from what I saw on my phone. I could not tell, but did you consider this test successful?
 

asadof

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Asadof,
In post 199, you attached a video of the landing gear being tested. It seemed to work well from what I saw on my phone. I could not tell, but did you consider this test successful?
It was a very simple test, you need to apply more force !!!
Because more gravitational force is applied
 

asadof

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Of course, I mean in critical situations and hard landing
Normally excellent
 

asadof

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I would prefer this discussion stay public. People here are smarter than I am, and will correct me if I give incorrect information.
Yes that's right
Since I did not notice the translation, my intention was to send a private message
 
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