India Class Helpful Information for Teams and Teachers

The Speedfest organizers have compiled some additional information that India Class teams may find useful.  Expect this page to be updated as questions arise.


Advisors, mentors, and team members must make sure they are working and operating their aircraft safely.  It is recommended that advisors and mentors ensure that the teams always comply with the Speedfest Safety Requirements and General Aircraft Requirements.  Even when not at the Speedfest event.


Building Advice
Additional learning ideas for team advisors
How to be more competitive


Building Advice

Before you begin!  Read the complete India class rules page from top to bottom carefully.  Then, read the instructions carefully and watch the video for the kit (listed on kit instructions).  We receive multiple questions about the rules, procedures, and the kits, that need not have been asked if the team would have done some careful reading beforehand.

Before beginning construction, consider making full size copies of the plans, or at least tracing kit parts to make templates.  That way if you want to build another airframe, or if you need to make major repairs, all you need to do is buy foam, and not another complete kit.  This will be significantly less expensive, and eliminate the need to rely on the continued availability of the kit (which are manufactured in small batches).  It will also allow for mistakes, or the opportunity to have different teams build multiple airframes if you have a large class and want to get more people involved. 

One source of useful information is "build threads" which are forums where people share their experiences building a particular plane.  It is often a nice way to supplement the instructions.  Also, you may submit questions and comments yourself, and people are often eager to help. 

Here are some very helpful resources for the 2022 contest planes:



Some additional learning ideas for team advisors

The Speedfest India Class project can be considered scalable.  Small teams can compete working after school, and also teachers could incorporate the project into their curriculum as an aerospace engineering project for larger teams.  Small teams may have the time to just complete the kit and perform some basic flight testing before competing.  Teachers of larger teams may want to incorporate more supplemental learning activities appropriate for their classes.  This section is intended to provide some ideas for subjects that will enhance student understanding as well as possibly assist the team with competitiveness.

A word of advice:  Within the RC hobby world, there is a wealth of information.  Unfortunately there are also a lot of myths, legends, and inaccurate science and engineering.  Consider this when searching for information.

The Academy of Model Aeronautics (AMA) has an education section on their website that contains useful information for teachers and students.  The information include such topics as; the basics of flight, scholarship opportunities, grant opportunities, educator materials, etc.

A technique that we have found to be very useful to teams working on competitive projects like this, is to conduct a rules test prior to commencing the project.  A lot of time is saved, mistakes reduced, and team communication improved, when all team members are equally aware of the requirements for the project.

Propulsion
The following subjects in propulsion are key for the India Class planes: Batteries, motor, ESC (electronic speed control), and propellers.    The propellers that are used are examples of fixed, constant pitch propellers.  There are a several manufacturers of propellers, and a variety of materials used in their construction.  Recommended propellers are APC Thin Electric type which are available for purchase at multiple vendors

Motors

Internal combustion (IC) engines operate very differently than electric motors.  An electric motor will continue to draw whatever power is necessary to drive the load while trying to maintain a constant rpm.  Conversely, the power of an internal combustion engine is based on the rpm which will vary significantly with the load.  So, on an electric propulsion system, increasing propeller size will increase the power draw, but on an IC engine, increasing propeller size beyond a certain point will actually decrease power.  This is why it is so critical to run a variety of tests in order to select the optimum prop for a particular mission. 

Additional speed may be obtained on an electric propulsion system through a combination of increasing propeller size or increasing pitch.  However, if power draw is increased too much, the motor/esc can be damaged, or battery power may run out before completing the mission.   The best way to optimize is to fly laps with variations in the propeller and determine the best.

Propellers

The propeller is one of the most complicated and nonlinear devices on the airplane.  Small changes in propeller can have very large effects on thrust and power.  For example:For safety, it is a good idea to paint both sides of the tips of the propeller a bright color.  This will significantly increase the visibility of the propeller when spinning, and reduce the chances of someone inadvertently putting thier fingers through the blades.

Make sure you balance your propellers using some type of prop balancer.  An out of balance propeller can cause excessive vibration, and can be dangerous.


Aerodynamics

Since the kit is fixed, significant aerodynamic changes are most likely not beneficial.  However accuracy and care in construction can have a beneficial effect:

Teams should do what they can to reduce drag in order to increase speed.  Properly applying covering material is one way to reduce drag.  Make sure covering is tight with minimal wrinkles.

When sanding aerodynamic surfaces and shapes, take care to avoid discontinuities and other types of bumps or protrusions.  Accurately shape and round the aerodynamic surface leading edges.  Avoid gaps as much as possible.


Structures

Aerospace structures are designed to be lightweight and strong.

Follow instructions carefully when putting parts together.  Make sure the fit together well.  Gaps reduce strength of the structure and the adhesive bond.


Flight Stability and Control

Make sure that the center of gravity (cg) for the airplane is where the manufacturer recommends.  Take care to accurately measure the CG location.  An aft cg will reduce the stability of the airplane, a forward cg will reduce turning ability.  It is a good idea to mark the required cg location on the airframe so that it is easy to quickly check it.

"Slop" in control surfaces make airplanes more difficult to fly, and can even make the airplane feel unstable to the pilot.  Make sure control surfaces and control actuators are firm.

Control surface throws have a significant effect on how the plane "feels" to the pilot.  This is called "handling qualities."  Control throws that are too small do not allow the plane to be fully controlled.  Conversely, control throws that are too large, reduce handling qualities, and make the airplane too sensitive to input.  Test turn rate by decreasing and increasing elevator throw.   Turning faster will reduce lap time.  Turning too fast will increase drag too much and possibly stall the wing and can lead to loss of control.


How to be more competitive

Some basic rules of thumb