# Aerobatic Tandem Two-Seater

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#### Lendo

##### Well-Known Member
Rad 123, I have just completed a Spread Sheet, it's short and simple, jut put in your proposed Span and Wing Area and automatically, does a lot of things for you like confirming Wing Area, Ht and VT area with lever arms, with lever arm adjustment for comparison with standard Volume coefficient, with all formula provided. You can take the new Wing Area answer and manually reenter that into the program until you get the ability to both adjust either or both the Span and Wing Area until you get a more accurate result - in the event your original entries were unrealistic.
I did this for my own benefit as I was wanting to easily define all these parameters with the minimum of entries and adjustments.
If you want this it's an Excel file, just post me privately and I will sent it to you with a copy of my Tandem design, you might get ideas of what I alluded to with changes to the tail.
George

##### Well-Known Member
Thanks for the offer, but I have my own spreadsheet that calculates the preliminary sizing info (such as the aerodynamic surface areas, tail volumes, static stability). That data is then combined with weight distribution to provide both static stability and stability derivatives. The stability derivatives are then fed into a Matlab program to give a dynamic stability analysis. Am currently working on adding flutter analysis to the spreadsheet.

Very interested in seeing what you mean with the tail tho!

Current canopy scheme:

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#### Lendo

##### Well-Known Member
Rad 123 Spin Recovery requires from 1/3 unblanked Rudder up to 50%, I used 50% by lifting the tail and taking the rudder down past the rear fuselage into the Ventral Fin area to get that 50%. Notice also the Ht position with Elevator forward of the Rudder.
All I need now is to win Lotto to built it with a Rotary Engine.
George

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#### Lendo

##### Well-Known Member
Rad 123, I will certainly keep in mind what your Spread Sheets can do. I can now see your onto the HT position - good one.
George

#### BJC

##### Well-Known Member
Current canopy scheme:
Have you determined if it will be possible to get out to parachute?

BJC

##### Well-Known Member
Have you determined if it will be possible to get out to parachute?

BJC
Was just thinking about that and why I revised it:

For the front: Unlatch, Pull hinge, Roeger Hook -> Canopy front lip is pushed up to catch the airflow and Roeger hook prevents it from sliding straight back to hit the pilot in the face.

For the rear: Pull hinge, unlatch, hinge stays attached until canopy rotates back to a certain angle.

Also thinking about a BRS, but internal space with this type of aircraft is always at a premium...

#### Lendo

##### Well-Known Member
RAD 123, Do you have a method of calculating 'Wing Load Testing' along the Semispan, I have included 'my system' in my SS for those who might have trouble visualizing and therefore carrying-out that to form a valid and clearly understood record.
Also I'd like to contact you privately to cross check your figures against mine for a range of things.
George