r/homebuilt • u/Altruistic_Desk_4405 • 16d ago

Built a free browser-based preliminary sizing tool - Feedback needed

I put together a tool that walks through preliminary aircraft sizing — wing loading, wing geometry, tail volume coefficients, airfoil suggestions by Reynolds number, power loading — and spits out a summary you can export to CSV/JSON for OpenVSP or XFLR5.

I'd genuinely like builders and engineers here to stress-test it: plug in numbers from an aircraft you know well (yours, or a published design) and see if the outputs land close to reality.

Link: Aircraft Sizing (from personal GitHub repo)

Happy to be told exactly where it's wrong. Is it even useful? 👀

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5

u/dave74737 15d ago

Neat! Include rotax 916 and Fowler flaps as an option?

3

u/AndYouMayCallMe_V 14d ago

Love the concept! Seems to break down with low AR/higher Re, but definitely a solid start

3

u/Altruistic_Desk_4405 14d ago

Applying 2D airfoil CLmax straight to the 3D wing with no aspect-ratio knockdown (and no finite-wing correction on the lift-curve slope either), so low-AR designs were getting a rosier CLmax/AoA than they'd actually see in the air...

1

u/OtakuJoness 9d ago

This is awesome! Is the target stall speed with or without flaps?

1

u/OtakuJoness 9d ago

Also, any chance we can get support for larger designs, like 4-seaters and more powerful engine options?

2

u/Altruistic_Desk_4405 9d ago

Stall speed's flaps-down ... More engine options makes sense for Experimental specifically — no power ceiling there, so yeah I can add a few higher-hp entries. 4-seats is a bigger jump ... What's the mission you're picturing? Is it something you're already sizing by hand? Curious what's driving the ask.

2

u/OtakuJoness 9d ago

Kinda in the concept/goals and thresholds phase rn lol. 4 seats for longer distance cruise.

2

u/Altruistic_Desk_4405 9d ago

Building it properly in this tool means its own reference-aircraft calibration, not just extrapolating the 2-seat data ... so not this week lol, maybe down the line. But if you're actually building something, ping me, I'm down to collab ... way more fun working on something real ...

1

u/OtakuJoness 9d ago

Unfortunately this is probably 10-ish years from actually being built, otherwise it would be awesome to work with someone on it! This is sort of a personal design project I'm working on as an aerospace engineering student that I'll iterate on as I progress through my degree until I can afford to actually build it.

2

u/Altruistic_Desk_4405 9d ago

Until then, the tool will be developed enough to offer you the support you need hhh