Aircraft Design Tutorial: Aircraft Mission Analysis by Example

[@michaelhajjar4132]

Always a joy to see a new video pop up here. Hope all is well

[@dr.gudmundssonaircraftdesign]

Good to hear from you, Mike. All is well, thank you, and I hope the same holds for you. Best wishes!

[@simpilot001]

A post? This is quite a once in a lifetime event I am witnessing

[@liamliam-q5d]

thank u a lot for this explication

[@dr.gudmundssonaircraftdesign]

Happy to help

[@SyedMujahid-vm1xo]

Thank you for the vedio, there is a quite mistake in the question, you have given empty weight ratio as Wp/Wo instead of We/Wo..

[@dr.gudmundssonaircraftdesign]

I know. It is already stated in the description, but thanks anyway. Best wishes.

[@SyedMujahid-vm1xo]

@@dr.gudmundssonaircraftdesign sorry sir, I didn't noticed in description. Sir can you provide a vedio for weight estimation of evtol(for this type of mission profile), it would be greatly appreciate sir. Thank you.

[@dr.gudmundssonaircraftdesign]

@@SyedMujahid-vm1xo No problem regarding discovering and reporting a mistake. No worries. I will consider your request for a video, but cannot guarantee if or when. In case you want to tackle such a mission analysis yourself, for electric vehicles you consider the consumption of battery energy in kWh rather than weight or mass of fuel. This, in turn, requires you to estimate power requirement during a segment (e.g. 100 kW) and its duration in hours (e.g. 30 min = 0.5 hr => Ebatt=0.5*100=50 kWh). Best wishes.

[@SyedMujahid-vm1xo]

@@dr.gudmundssonaircraftdesign thank you sir, will be waiting 😊

[@gendaminoru3195]

And of course "node 4" neglects regulatory required reserve fuel, ie airline 121 dispatch fuel or IFR NBAA reserves, etc

[@dr.gudmundssonaircraftdesign]

@gendaminoru3195 Yes, Node 4 does. But then again, this is a super-simple example intended to primarily explain the process to the new-comer. The next steps are for the new-comer to increase complexity by accounting for requirements such as those that you bring up. Example 6-4 in my book shows how this can be done for a Falcon 900 class business aircraft. Best wishes.

[@gendaminoru3195]

@@dr.gudmundssonaircraftdesign And you as well - wishes. Do you ever get to the level of Illan Kroo from Stanford? I have all of his materials and all the stuff from Douglas and McDonnell Douglas for twinjets and some Trijet data from our Boeing agreements. I think a lot of DC-9 is in the public domain though. I do like your approach.

[@freezatron]

Hi, do your books explain how to implement and use the unusual math symbols ? .. such as capital Pi, what ever that means :) Would be very helpful if your books contain a primer with a few examples to aid the novice aerodynamicist how to use the more obscure maths components etc. I'm looking at this from the point of an amateur wanting to design, build and fly their own ultralight aircraft without the need of having to do a two + year maths course just to understand a handful of maths components critical to understanding how to design aircraft safely. Also, do your books cover structural engineering ? I've managed to gather some information from youtube, such as moment areas and the like but I'm struggling with resolving trusses etc. A book that explains such things in a manner that an amateur could understand would prove most useful. Thank you.

[@dr.gudmundssonaircraftdesign]

Hi freezatron. Thank you for your message. Capital Pi as a product symbol is not any more mysterious than the Capital Sigma symbol used to represent a sum of terms. Anyway, you may want to visit amazon dot com and check out the book there. Amazon has a preview feature that allows you to look inside books before you buy. I think you will find it has a lot of mathematics. This is inevitable in a college level textbook. My book has some, but rather limited structural analysis because it focuses on the conceptual design rather than detail design (that's where you design the airframe). For truss analysis you need to study the engineering discipline called "Statics." Hibbeler has a widely used textbooks that has a lot of numerical examples. There are number of others that might suit you. Google "textbooks on statics" or similar. Best of luck with your design.

[@freezatron]

@@dr.gudmundssonaircraftdesign Thank you for your reply, but Capital Sigma is something I've not heard of that either, I wonder if your familiarity with such terms has allowed you to forget what it's like for the layman :) I'm fine with doing the maths if I understand the terms and the units involved but when I come across terms such as Capital Sigma I come unstuck. I know how to use the lift equation, the drag equations are less known to me as there are a few of them and I have some questions that I need asking before I can use them with confidence, without them I can't put together a proper flight profile or size the engine etc. There are some videos for the layman I would like you to make but I would want to impose upon your generosity. Thank you for letting me know the name Statics, difficult to search for things when you don't what they're called :) The design I am working towards is a foot launched aerobatic glider with a Reynolds number in the half to two million region, I seem to know enough to conceptualize something within in reality but not quite enough to describe it accurately ... Thank you for your help, it's much appreciated.

[@dr.gudmundssonaircraftdesign]

@@freezatron I appreciate your comments, but don't forget that my videos are not intended for laypeople, but for practicing engineers and students of aerospace engineering. Anyway, be careful when dealing with structures. Truss analysis and structural analysis is not simple. If you try to analyze something, try to find a structural engineer willing to review the work. I suggest you let that person know that he/she is not responsible for anything. You are just asking for some guidance. You're also welcome to list what video topics you're interested in. I am not promising I will make them, but then again one never knows. Best wishes.

[@freezatron]

@@dr.gudmundssonaircraftdesign Thank you kindly for making time to reply to me, it's much appreciated ! I fully appreciate who your target audience is but I subscribed to your channel regardless because it has been helpful for me to glean some useful snippets from your videos,. It has always been my intention to learn enough to be able put together a detailed presentation for a qualified engineer to verify my work and highlight any holes in my understanding. Naturally as a pilot I will take full responsibility for my own designs, builds and safety. My wish list of subjects are as follows - 1) An explanation of the various drag formulas at standard sea level atmospheric conditions, induced, form, profile, parasitic, incidence drag etc. No need to complicate it with a variety of viscosity calculations for a variety of density altitudes, that would require a video of its own. I want to know what my drag is at a 1 G level stall, best L/D, drag at maximum G and drag at VNE, also with and without flaps deployed. 2) To assess the ultimate loads on the controls and relevant surfaces I need to know how to calculate the forces on the control surfaces at the designated maximum G loading as well as maximum deflections at the designated VNE. If I know what the torque is at the hinge line I can work out the rest from there, I think. 3) A refresher on cantilevers using the moment area calculations to find out the ultimate load of the wing spars for the designated max G just to make sure I have understood this properly. The two materials I am looking to choose between are aluminium and carbon fibre. 4) resolving trusses and tubes buckling under compression loads. I know this is a complicated subject but it seems important for me to understand. 5) A refresher on the shear loads for wing bolts would also be a good thing to include too. I know there are some calculators available for some of this but they don't help me actually understand it, which is really what I want, at the very least knowing the above will allow me to have an informed conversation with qualified engineers and make better design decisions. Ideally the format of these videos might be - -An introduction to the formulas and what it is calculating for. -The components of the formulas. -The units used for each component imperial or metric, I can use either. -Followed by some step by step practical examples that are complete step by step leading to a result that can be applied such that I can plug in my own numbers and use the formulas with some confidence like I can with the lift formula for example. From what I've seen on youtube of the above formulas, they all seem to use relatively straight forward mathematical terms to solve them in the long handed manner, I know that multiple iterations can be condensed into one formula with calculus or with capital Pi etc. which is alien to me, apologies. I can however follow the long handed methods if I have a well explained example I can follow. I have found to my frustration that these videos either don't explain their examples well leaving me with unanswered questions, skipped crucial steps assuming knowledge on the part of the audience as to how they arrived at that conclusion or just flat out not explaining the units properly making the subject more dense than needed. Either way I am left staring at a formula I can't actually use and apply. I am ever so grateful for your even replying to me let alone your kind consideration of the above subjects. I fully appreciate you're a busy man with many of your own students to attend to. That said my hopes are high but my expectations are low and I shall consider any knowledge you are kind enough to share as a bonus towards my own projects and understanding. Perhaps one idea that might appeal to you is to give your students an assignment of making a video for your channel where in they demonstrate their knowledge by explaining concisely and clearly on a given aspect of a subject that can be applied in a practical manner. Clear and concise enough for a layman to grasp in order to demonstrate that they have a solid understanding of the fundamentals :) Thank you again for reading my comments and making the time to reply, it is hugely appreciated. Kind regards.