UAS Challenge


UAS Challenge - Your questions answered

FAQs 2022

Airframes: Ready-made or made for the competition

Are we allowed to use ready-made frames/structures for our unmanned aircraft or do we make it from scratch? 

: The rules are quite clear that airframe kits are not permissible – para 3.1.13:

“The UAS airframe and control systems shall be designed from scratch, and not based upon commercially available kits or systems.’’  The airframe and control systems design should be your own and not a copy of a commercial UAS.  We are looking for innovative ideas.

Aid package specification – external dimensions

The dimensions given in section 3.1.4 of the Rules are for the internal dimensions of the container, what are the external dimensions of the container and parachute?

Answer: The overall dimensions of the ADB Micro box are 15 cm x 12.5 cm x 30 cm. The standard parachute adds 7 cm - 10 cm to the length, and is about 17 cm x 17 cm in width / height.

Aid package specification – container modification

Are we allowed to add a small tab to the payload to be a part of the payload release mechanism or add a nose cone to reduce drag?

Answer: No, you are not permitted to modify the payload container in any way, including attaching fixings to it. You may make modifications to the parachute.

Aid package specification – carriage

Do we have the option to carry the payload on the inside or outside of the airframe?

Answer: You may carry the payload on the inside or outside of the airframe but you must not modify the container in any way.

COTS: 2. 3.1.13 Limits on use of COTS Items

The UAS airframe and control systems shall be designed from scratch, and not based upon commercially available kits or systems. This is a qualifying rule, meaning that an entrant based on a commercially available system will not be eligible for consideration. We would like to buy a flight controller which has many integrated systems. Are we allowed to use such commercially available set of hardware? 

Answer: The note in para 3.1.13 lists the type of stock components that are permissible as COTS items. We want you to design your own airframe but you are permitted to use off-the-shelf autopilots.

COTS: Camera

Does the camera count as an off shelf component that is part of the suggested budget?

Yes, the camera counts as a COTS item and should be included in your COTS budget.

COTS: Products budget - what is included?

The COTS products budget is set at £1000. I am aware this includes off the shelf components such as motors and batteries etc. Does this also include all material and manufacturing costs too? Is the cost of either the sandwich panel itself or the associated manufacturing costs included in this COTS budget?

Answer: The rules state that the guideline maximum value of COTS is £1,000; it is not a limit but we are looking for the best value for money (competitiveness) of the UAS. COTS, in this context, is for bought-in finished components, e.g. motors, batteries, servos, control boards, etc.  Materials that the team will be using in the manufacturing of the UAS would not be included in COTS.

Deliverable documents: Structure and content of deliverable documents

Annex F specifies the structure and content of the deliverable documents.  Is this mandatory or guidance on how to cover the subject matter? 

Answer: The structure, word and page counts are mandatory.  The sections will be split up for assessment by different judges and, therefore, it is important that you clearly follow the individual section content, including the information required on the cover page.

Electrical power system – energy source

Is it permissible to use power sources other than Li-Po batteries e.g. hydrogen fuel cells?

Answer: There are no restriction on the power source. As with all aspects of your design, you must fully address the safety of manufacturing, testing and demonstration and make provision for any safety equipment necessary. You should also consider the environmental impact of your design choices.

Electrical power system – removable link

If we have a two-engine design does it need to be one isolator, or can a two-engine design run on separate circuits with one for each engine?

Answer: The requirement for the external removable link is for the safety of the operator and so that the Scrutineers and Flight Safety Officer can see that the aircraft is in a safe to handle state. If you were to use 2 links, they would have to be tethered together so that you could not only remove one, leaving the aircraft in a potentially unsafe state.

Design Changes

Once the concept paper is submitted, how much is our design allowed deviate from it In case we encounter problems?

Answer: You may make detail changes to your design at any stage as your design evolves and as testing raises issues. You must list any significant changes with an explanation of why they have become necessary in your next document release.

Funding: Backup components

If we acquire backup components for the build that may not be used in the final system during the flight missions, should we include it in the budget/ cost declaration?

Answer: No, you need not declare backup components in your cost budget but you may want to mention that you have taken the precaution of buying some as a risk mitigation.

Flight demonstration: Dronekit

Is it allowed to use Dronekit for the path planning?

Answer: Yes, but it will need to be accounted for in the COTS budget and do not forget that there are points for innovation.


Flight demonstration: Core mission – climb and glide circuit

In the climb and glide portion of the flight demonstration, can we complete the glide around a custom circuit or does the glide need to occur round the same circuit as the powered flight?

Answer: It is a custom circuit, not a repeat of your powered circuit.


Flight demonstration: Core mission – climb and glide power-off precision landing

Can we engage the motors at any point during the glide or landing i.e. could we engage the motors at the point of touchdown to reverse thrust and ensure we don’t run out the 30m box?

Answer: No, you may not engage power at any point during the glide or landing.


Flight demonstration: Core mission – power logger

Annex D states “each monitored circuit shall have a continuous current draw of 60 A or less in operation”. Is it permissible to have a single motor circuit drawing more than 60 A continuous?

Answer: Yes, you can draw over 60A continuously by using 2 Power Loggers in parallel.
Please note that the manufacturer of the Power Logger is no longer trading but the IMechE has a stock of Power Loggers that will be used at the Demonstration Event.


Flight demonstration – Catapult Release

Can we release the catapult by hand and do we need to be a minimum distance away?

Answer: You can hand launch your aircraft or manually release your catapult without risking penalties under the Automatic Operation requirement. You must undertake a risk assessment to determine how this is to be done safely and not pose a risk to the launcher or anyone else. The FSO will not permit release if he/she is not satisfied that the risk has been adequately addressed. Similarly, if using a catapult, your risk assessment will determine whether you can safely install the aircraft after the catapult has been set.


Flight demonstration: Failsafe system

Does the failsafe system need to remove power to the motors or can the failsafe system simply remove the control signals to the electronic speed controller which in turn shall prevent the motor using power (both ways will bring the motors to a standstill and the UAV to a safe glide to ground)?

Answer: The means by which you achieve the engine shut down is up to you but as this is a key safety issue you should satisfy yourself that your design is of high integrity and will operate immediately that the FTS system has been triggered either through loss of the link or commanded by the Flight Safety Officer.

Flight demonstration: Launch/landing surfaces

In the competition document it says that the aircraft should operate on grass or hard runway surfaces. Does this mean we get to choose whether we want to launch/land on grass or asphalt runway?

Answer: You are required to be able to do either but the take-off and landing site will be chosen and designated by the Flight Safety Officer at the start of the flight demonstration event.


Flight demonstration: Marker placement

The rule states: “The accuracy of the marker placement shall be within 30m of nominal course”.
  • Does this mean that the marker shall be within a 30m bound total or 30m either side of the UAV flight path?

    Answer: It is not clear what you mean by “a bound total” but the rules clearly state that the Ground Markers will lie on a straight line between waypoints within a placement accuracy within 30 m either side of this straight line.
  • Will the placement of the marker be on a straight within the two waypoint or can the marker be placed a point where the UAV is required to bank?

    See above but they will not be placed so close to a waypoint that your vehicle will still be turning if it is following the correct course.

Flight demonstration: PPE requirement

Could you please provide a full list of all PPE that the team will require to be compliant with your risk assessment?

Answer:  The PPE requirement will vary for each team, depending on what tooling they bring with them to use at the event, therefore, no specification will be provided by the IMechE; if we did it would state “all PPE required for the tasks to be performed”.

Teams should be advised to consult the Health and Safety Executive (HSE) guidance for PPE at work and demonstrate to the IMechE that they have selected suitable PPE for the maintenance/manufacturing tasks they will be performing, as part of their own Safety Assessment/Risk Assessment as part of the Concept Paper, CDR and FRR deliverables and through volunteer observation of PPE usage at the event.

Flight demonstration: Reconnaissance mission - target design

While the brief does provide a good idea of what the targets will look like, it is possible that the physical manifestation of these could differ on the day. Are any photos of previous targets available for reference?

Answer: The dimensions will be adhered to but the exact formation of the letter may vary. Unfortunately there are no photographs of previous year’s targets but these would not necessarily be helpful.

Flight demonstration: Reconnaissance mission - target design fonts

I assume that the characters will be hand-painted so will not be of a particular 'font'. That said, can you confirm that they will be similar to standard sans-serif fonts such as that used in the brief?

Answer: They will be handmade but will be as near as possible to the font shown in Figure A1.

Flight demonstration: Reconnaissance mission – target design alpha-numerics

For image recognition, will targets that feature 6s and 9s or other orientation ambiguities be distinguished by a line?

Answer: We will not use potentially ambiguous alpha-numerics.

Flight demonstration: Reconnaissance mission - target example

Could you post an example picture of the actual target? Knowing the material and character font would allow us to fine tune the object detection system. I'm sure all the teams would benefit from having this.

Answer: No, you are only being given the approximate dimensions in the rules.

Flight demonstration: Reconnaissance mission - video downlink range

Regarding the video downlink, is the 1km range a strict requirement even if the video downlink is not essential in the operation of the UAS? Telemetry and RC will of course comply with the 1km range.

Answer:  No, you do not have to achieve a 1km range for the video downlink if it is not critical to the operation of the UAS but it must comply with EU directives and be licensed for use in the UK. All a/c are flown within Visual Line Of Sight (VLOS) rules iaw CAP722/CAP393, therefore, any video imagery is not essential for Safety of operation.

Funding: Declaring sponsor's assistance/costs

We have a sponsor who will be helping us fabricate our frame. If we have to, how do we declare the costs associated with this?

Answer: You need to clearly state what work your sponsor is doing for you. Please take particular note of the words in sections 2.6 and 3.1.15 (particularly 4th paragraph) of the Rules.

The idea of the competition is that this should be your own airframe and control system design and aside from off-the-shelf components, e.g. autopilots, batteries, motors, etc. should largely be manufactured and assembled by yourselves.
f it is a specialised component/assembly from your sponsor then it should be included in the COTS budget. If the sponsor is helping with specialised manufacturing equipment then it need not but should be acknowledged.

Funding: Financial assistance/grants

Is it possible for the Institution of Mechanical Engineers to help our team financially in order to cut down costs? The Institution is not able to sponsor any teams but you are eligible to apply for a Group Project Award 

Motor Design

Is it permissible to have a single motor circuit drawing more than 60A continuous from the battery?Yes, you may do so but you will need to use 2 Power Loggers in parallel to monitor the power usage

Team composition: Original team membership numbers

If we want to add an additional member to the team (giving more than 10 people + supervisor) is this possible?

Answer: Team attendance at the Demonstration Event is currently limited to no more than 10 members per team, plus your Academic Lead or Team Supervisor.  This is because of the expected number of teams and the logistics constraints at the BMFA Buckminster site.

Team composition: Team supervisor

Can this just be anyone, for instance, someone from the team, or does this have to be someone more official, such as a university lecturer?

Answer: The team supervisor should be a university staff member.

Team Composition (Part 2.5.1)

Our recommendation is that 70% of your team is in its final year or postgraduate, due to the complexity of the competition and the opportunities with industry partners that we provide - which are most likely to be of interest to penultimate and final year students.

Maximum Cost of £1,000

3.1.15 of the Rules suggests that you should not spend more than £1,000 of COTS components in the UA itself (your ground station laptop, etc. is not included in this £1,000). 3.1.15 lists the components that we are classing as COTS for this purpose. The £1,000 is not a hard limit but you may struggle to make a good business case for your UA if you spend significantly more than this. You are not limited to what you spend on materials but you do need to consider whether an aid agency will be able to afford your UAS for delivering the humanitarian aid. We will be judging your business case from your Dragon’s Den presentation. You also need to consider the environmental impact of the materials that you are using.

Why do I have to pay to formally register?

The team registration fees are used to help the Institution cover the running costs of the UAS Challenge. The student challenge portfolio is expected to break even and that is one of the reasons we engage industry partners who help us finance the competitions annually.

All participants are expected to pay the registration fees and many teams engage with local companies and have managed to secure sponsorship that helps them to cover the costs.

The IMechE helps provide funding via our grant schemes.

Does our Team Leader have to be a final year or postgraduate student?

Our recommendation is that the team Leader is a final year undergraduate or postgraduate student. It is important to ensure that your team leader has the skill set and ability to manage the team.

If you are having difficulty finding a suitable team leader that fits the above criteria, you may appoint a leader who is not a final year undergrad/ postgrad if they meet the other requirements at your own discretion.

What is permitted as a “modification” to the parachute and what is not?

You may modify the parachute in any way that you like including replacing it with a parachute of your own design but it must attach to the box in the same way. You may not modify the box in any way.

What is KIAS?

KIAS is Knots – Indicated Airspeed and is the speed of the aircraft in the air as measured by your pitot-static system. It is not the same as GPS groundspeed. You should look into understanding IAS as it is an important parameter in the design of an aircraft

Clarification on Pilot licenses

All flying at the competition event itself will be conducted by the event Safety Pilots and myself as Flight Safety Officer, so the teams will not actually fly themselves at the competition. In terms of your own practice and testing, teams just need to comply with the UK Civil Aviation Authority regulations and the UK Air Navigation Orders for safe and lawful flying.

In summary UK teams must ensure the following:

  1. That they or the University hold an Operator ID form the UK CAA and that said number is displayed correctly on their aircraft.
  2. That any person flying the aircraft meets the competency requirements set out by the UK CAA, which is typically the Flyer ID element.
  3. That any flights are only performed under UK CAA regulations, i.e. that they fly safely and lawfully. As they are likely to be flying aircraft near 10kg, this will mean they are likely to be flying in the A3 Open Category.
  4. The dropping of articles from an unmanned aircraft is NOT permitted in the Open Categories, i.e. it is illegal, so practicing this is not possible unless they join an association with access to an Article 16 permission, which I will be drafting an email for all teams very soon.

There is no official need legally for insurance unless any flights are considered ‘commercial’, however I believe the IMechE do request that teams use insurance, for which the British Model Flying Association can help Joining the BMFA also gives access to their Article 16 permission, which is required if teams want to test and practice payload dropping. Follow up email coming soon as mentioned above.

A quick start guide on regulations can be found here:

Commercial flying is often considered a flight performed for payment or reward, but if the pilot is a paid member of staff, that also makes it a commercial flight.

International teams:

International teams will need to comply with their relevant Aviation Authority regulations, which may differ to those in the UK.

Clarifications on the dropping process

You may not drop anything from the aircraft other than the payload and the payload box must not be modified.  If you want use some form of fairing over your payload you must arrange for this to stay with the aircraft and this should give you an opportunity for some innovative design.

You can alter or change the parachute, but you should not be designing a fairing or structure to encase the payload when released to alter drag or add increased structural support, as this defeats the purpose of us suppling the payload you need to deliver.

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